CN112694843A - Adhesive impact absorbing layer and laminate comprising same - Google Patents

Adhesive impact absorbing layer and laminate comprising same Download PDF

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Publication number
CN112694843A
CN112694843A CN202011138611.4A CN202011138611A CN112694843A CN 112694843 A CN112694843 A CN 112694843A CN 202011138611 A CN202011138611 A CN 202011138611A CN 112694843 A CN112694843 A CN 112694843A
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adhesive
absorbing layer
meth
acrylate
impact absorbing
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朴钟一
黄柱盛
文根镐
李愚择
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Iljin Materials Co Ltd
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Iljin Materials Co Ltd
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    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J5/00—Manufacture of articles or shaped materials containing macromolecular substances
    • C08J5/18—Manufacture of films or sheets
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J7/00—Adhesives in the form of films or foils
    • C09J7/20—Adhesives in the form of films or foils characterised by their carriers
    • C09J7/22—Plastics; Metallised plastics
    • C09J7/25—Plastics; Metallised plastics based on macromolecular compounds obtained otherwise than by reactions involving only carbon-to-carbon unsaturated bonds
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B27/00—Layered products comprising a layer of synthetic resin
    • B32B27/28—Layered products comprising a layer of synthetic resin comprising synthetic resins not wholly covered by any one of the sub-groups B32B27/30 - B32B27/42
    • B32B27/281—Layered products comprising a layer of synthetic resin comprising synthetic resins not wholly covered by any one of the sub-groups B32B27/30 - B32B27/42 comprising polyimides
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B7/00—Layered products characterised by the relation between layers; Layered products characterised by the relative orientation of features between layers, or by the relative values of a measurable parameter between layers, i.e. products comprising layers having different physical, chemical or physicochemical properties; Layered products characterised by the interconnection of layers
    • B32B7/04—Interconnection of layers
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J3/00—Processes of treating or compounding macromolecular substances
    • C08J3/20—Compounding polymers with additives, e.g. colouring
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K3/00—Use of inorganic substances as compounding ingredients
    • C08K3/01—Use of inorganic substances as compounding ingredients characterized by their specific function
    • C08K3/013—Fillers, pigments or reinforcing additives
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K3/00—Use of inorganic substances as compounding ingredients
    • C08K3/02—Elements
    • C08K3/04—Carbon
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K5/00—Use of organic ingredients
    • C08K5/0008—Organic ingredients according to more than one of the "one dot" groups of C08K5/01 - C08K5/59
    • C08K5/0041—Optical brightening agents, organic pigments
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L33/00—Compositions of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides or nitriles thereof; Compositions of derivatives of such polymers
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L9/00—Compositions of homopolymers or copolymers of conjugated diene hydrocarbons
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J109/00—Adhesives based on homopolymers or copolymers of conjugated diene hydrocarbons
    • C09J109/02—Copolymers with acrylonitrile
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J11/00—Features of adhesives not provided for in group C09J9/00, e.g. additives
    • C09J11/02—Non-macromolecular additives
    • C09J11/06—Non-macromolecular additives organic
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J133/00—Adhesives based on homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides, or nitriles thereof; Adhesives based on derivatives of such polymers
    • C09J133/04—Homopolymers or copolymers of esters
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J133/00—Adhesives based on homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides, or nitriles thereof; Adhesives based on derivatives of such polymers
    • C09J133/04—Homopolymers or copolymers of esters
    • C09J133/06—Homopolymers or copolymers of esters of esters containing only carbon, hydrogen and oxygen, the oxygen atom being present only as part of the carboxyl radical
    • C09J133/062—Copolymers with monomers not covered by C09J133/06
    • C09J133/066—Copolymers with monomers not covered by C09J133/06 containing -OH groups
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J7/00—Adhesives in the form of films or foils
    • C09J7/30—Adhesives in the form of films or foils characterised by the adhesive composition
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J2409/00—Presence of diene rubber
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J2433/00—Presence of (meth)acrylic polymer
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J2479/00—Presence of polyamine or polyimide
    • C09J2479/08—Presence of polyamine or polyimide polyimide
    • C09J2479/086—Presence of polyamine or polyimide polyimide in the substrate

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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Health & Medical Sciences (AREA)
  • Medicinal Chemistry (AREA)
  • Polymers & Plastics (AREA)
  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Materials Engineering (AREA)
  • Laminated Bodies (AREA)
  • Adhesives Or Adhesive Processes (AREA)

Abstract

The present application provides an adhesive impact absorbing layer comprising: a continuous phase comprising a first acrylic copolymer having a glass transition temperature of-50 ℃ to-20 ℃ and an elasticity imparting resin; and a dispersed phase comprising opacifying particles.

Description

Adhesive impact absorbing layer and laminate comprising same
Cross Reference to Related Applications
The present application claims priority from korean patent application No.2019-0131486, filed on 22.10.2019, the entire disclosure of which is incorporated herein by reference.
Technical Field
The present application relates to adhesive impact absorbing layers. More particularly, the present invention relates to a polyurethane foam having a smooth surface, while having excellent adhesive strength and excellent impact absorption function, and being suitable for use in a building
And an adhesive impact absorbing layer suitable for use in the adhesive film tape.
Background
Adhesive film tapes have been developed to meet various needs, and new articles have been developed. In various application fields, in the case of mobile devices such as mobile phones and tablet PCs, since these devices have been continuously miniaturized in thickness and volume for user convenience and are frequently carried around due to the nature of their use, they are easily exposed to the risk of damage or breakage caused by external physical impact. Therefore, various attempts have been made to develop a method of imparting an impact absorbing function to the adhesive film tape used for manufacturing these devices.
In order to provide the adhesive film tape with an impact absorbing layer, a material containing foam particles having an excellent impact absorbing function has been widely used for the impact absorbing layer. However, when foam particles are used for the impact absorbing layer, as the number of layers to be laminated increases, the surface curvature increases as shown in fig. 1B or fig. 1C, and thus a so-called orange peel phenomenon or the like occurs, which reduces the aesthetic property.
Further, when foam particles are used for the impact absorbing layer, the surface of the impact absorbing layer inevitably has low adhesive strength due to the presence of the foam particles on the surface as shown in fig. 4B or 4C. In order to compensate for low adhesive strength between the film layer and the impact absorbing layer, and between the impact absorbing layer and the article, it is necessary to coat an adhesive layer on both sides of the impact absorbing layer, which is an additional step, and thus it reduces the process efficiency and increases the process cost.
The related art documents include Korean patent laid-open Nos. 10-2018-0086559 and 10-2018-0055014.
Disclosure of Invention
The present application aims to provide an adhesive impact absorbing layer having excellent bending resistance.
Further, the present application aims to provide an adhesive impact absorbing layer having improved adhesion to a substrate at high and room temperatures.
Further, the present application aims to provide an adhesive impact absorbing layer that can be directly adhered to a polyimide film without any intervening adhesive layer, since the adhesive impact absorbing layer has excellent adhesion and impact absorbing properties.
Further, the present application aims to provide an adhesive impact absorbing layer having high pressure deflection (CFD) and excellent surface roughness even if foam particles are not contained.
Further, the present application aims to provide an adhesive impact absorbing layer having high Compression Set (CS) stability due to optimized heat resistance and fluidity.
Further, the present application aims to provide an adhesive impact absorbing layer having improved process simplicity and article reliability due to having high compression set stability.
Further, the present application aims to provide an adhesive impact absorbing layer suitable for use in an adhesive film tape.
Further, the present application aims to provide a laminate including the above-described adhesive impact absorbing layer.
All of the above and other objects of the present application can be achieved by the present application described below.
One aspect of the present application provides an adhesive impact absorbing layer. The adhesive impact absorbing layer may include a continuous phase and a dispersed phase dispersed in the continuous phase, and the continuous phase may include a first acrylic copolymer having a glass transition temperature of-50 ℃ to-20 ℃ and an elasticity-imparting resin, and the dispersed phase may include light-shielding particles.
The elasticity-imparting resin contains one or more selected from the group consisting of a second acrylic copolymer having a glass transition temperature of more than-20 ℃ and 10 ℃ or less, a butadiene-based rubber, and an acrylic rubber.
The weight ratio of the first acrylic copolymer and the elasticity imparting resin may range from 1.2:1 to 3: 1.
The light-shielding particles may include at least one of carbon black, a black pigment, and a color pigment.
The adhesive impact absorbing layer may have a CFD of 0.10MPa to 0.25MPa under 25% compression, and a CFD of 0.3MPa to 0.5MPa under 50% compression, an impact absorption rate of 40% to 60% as determined by a ball drop test performed by dropping a 13.8g steel ball from a height of 10cm, an adhesive strength of greater than 2,000gf/in and less than or equal to 5,500gf/in under conditions of a temperature of 23 + -2 ℃ and a relative humidity of 50 + -5% when determined by stretching at a rate of 300 + -30 mm/min, and an adhesive strength of 500gf/in to 2,000gf/in under conditions of a temperature of 85 + -2 ℃ and a relative humidity of 50 + -5%, and an adhesive force of 1,900gf/in to a substrate under conditions of a temperature of 23 + -2 ℃ and a relative humidity of 50 + -5% when determined by stretching at a rate of 300 + -30 mm/min, and an adhesive force of the adhesive impact absorption layer to the substrate is 600gf/in to 1,300gf/in under conditions of a temperature of 85 + -2 deg.C and a relative humidity of 50 + -5%.
Another aspect of the present application provides an adhesive impact-absorbing layer satisfying formula 1, wherein, in formula 1, CFD50 is CFD (mpa) measured at 50% of initial thickness, and CFD25 is CFD (mpa) measured at 25% of initial thickness, CFD (mpa) being measured by: a 10mm thick sample was prepared by stacking and pressing the material at a rate of 400mm/min and a load of 4kg using an automatic press roll, and the sample was pressed by lowering the upper plate at a rate of 5mm/min toward a load cell of 1kN using a Universal Testing Machine (UTM).
[ formula 1]
2.0≤CFD50/CFD25≤3.0，
The density of the adhesive impact absorbing layer may be 0.70 or more and less than 1.00, and the CS may be 90% or more.
The Rz surface roughness of the adhesive impact absorption layer may be 0.5 μm to 50 μm and the Ra surface roughness may be 0.01 μm to 0.4 μm.
The thickness of the adhesive impact absorbing layer may be 40 μm to 150 μm.
A further aspect of the present application provides a laminate in which any one of the above-described adhesive impact absorbing layer, polyimide film, and light shielding layer is stacked in this order.
In the laminate, the polyimide film is in direct contact with the adhesive impact absorbing layer without an intervening adhesive layer.
Drawings
The above and other objects, features and advantages of the present application will become more apparent to those of ordinary skill in the art by describing in detail exemplary embodiments thereof with reference to the attached drawings, in which:
fig. 1A is a Scanning Electron Microscope (SEM) image showing a cross section of an adhesive impact absorbing layer formed in example 1 of the present application at a magnification of 500 times;
fig. 1B is an SEM image showing a cross section of the impact absorbing layer formed in comparative example 1 of the present application at a magnification of 500 times;
fig. 1C is an SEM image showing a cross section of a polyurethane-based (open cell type) impact absorbing layer at a magnification of 500 times in a conventional impact absorbing layer article;
FIG. 2 is a cross-sectional view showing a cross-section of a laminate according to one particular embodiment of the present application;
FIG. 3 is a cross-sectional view of the structure of a prior art adhesive film containing foam particles;
fig. 4A is an optical microscope image showing a magnification of 50 times of the surface of the adhesive impact absorbing layer formed in example 1 of the present application;
fig. 4B is an optical microscope image showing a magnification of 50 times of the surface of the low-density impact-absorbing tape; and
fig. 4C is an optical microscope image showing a magnification of 50 times of the surface of the high-density impact-absorbing tape.
Detailed Description
Hereinafter, exemplary embodiments of the present application will be described in detail with reference to the accompanying drawings. However, in describing the present application, when it is determined that a detailed description of a related known technique or configuration may unnecessarily obscure the gist of the present application, the detailed description will be omitted.
Terms described below are defined in consideration of their functions in the present application, and should be defined based on the entire contents of the present specification described in the present application since they may have various meanings according to the intention of a user or operator, a client, and the like.
The exemplary embodiments described below are merely illustrative of the present application, do not limit the present application thereto, and may be modified or changed according to the configuration and conditions to which the present application is applied.
The adhesive impact absorbing layer of the present application includes: a continuous phase; and a dispersed phase dispersed in the continuous phase.
Hereinafter, each part will be described in detail.
Continuous phase
The continuous phase comprises a first acrylic copolymer and an elasticity imparting resin.
The glass transition temperature of the first acrylic copolymer is from-50 ℃ to-20 ℃ as determined by Differential Scanning Calorimetry (DSC) thermal analysis method. When this range is satisfied, the first acrylic copolymer has the effects of excellent adhesive strength and high impact absorption rate. When the glass transition temperature of the first acrylic copolymer is lower than-50 ℃, there is a problem in that the adhesive strength is significantly reduced, and when the glass transition temperature of the first acrylic copolymer is higher than-20 ℃, there is a problem in that the durability is reduced. Preferably, the glass transition temperature of the first acrylic copolymer is in the range of-45 ℃ to-20 ℃, e.g., -40 ℃ to-20 ℃.
The first acrylic copolymer may comprise 85 to 95 wt% of units derived from a C1-C12 alkyl (meth) acrylate monomer, 0.05 to 10 wt%, preferably 5 to 10 wt% of units derived from a hydroxyl-containing (meth) acrylate monomer, and 0.01 to 10 wt% of units derived from a copolymerizable monomer. When these ranges are satisfied, there is an advantage that the bending resistance is excellent.
Examples of the C1-C12 alkyl (meth) acrylate monomer may include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate, n-pentyl (meth) acrylate, isoamyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, octyl (meth) acrylate, nonyl (meth) acrylate, decyl (meth) acrylate, undecyl (meth) acrylate, dodecyl (meth) acrylate, and the like, but the present application is not limited thereto. Exemplary C1-C12 alkyl (meth) acrylate monomers can be used alone or in combinations of two or more of them. Preferably, ethylhexyl (meth) acrylate may account for 50% by weight or more in the C1-C12 alkyl (meth) acrylate, and when this range is satisfied, the adhesive strength of the impact absorbing layer may be improved.
Examples of the hydroxyl group-containing (meth) acrylate monomer may include a (meth) acrylate having one or more hydroxyl groups. For example, the hydroxyl group-containing (meth) acrylate may be one or more selected from the group consisting of: 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, 1, 4-cyclohexanedimethanol mono (meth) acrylate, 1-chloro-2-hydroxypropyl (meth) acrylate, diethylene glycol mono (meth) acrylate, 1, 6-hexanediol mono (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol penta (meth) acrylate, neopentyl glycol mono (meth) acrylate, trimethylolpropane di (meth) acrylate, trimethylolethane di (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, glycidyl (meth) acrylate, and the like, 4-hydroxycyclopentyl (meth) acrylate, 4-hydroxycyclohexyl (meth) acrylate, and cyclohexanedimethanol mono (meth) acrylate. Preferably, the hydroxyl group-containing (meth) acrylate is one of (meth) acrylates including a C2-C4 alkyl group having one or more hydroxyl groups, such as 2-hydroxyethyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, and 4-hydroxybutyl (meth) acrylate, or a combination of two or more thereof. The hydroxyl group-containing (meth) acrylate monomer is contained in an amount of 5 to 15% by weight, for example, more than 5% by weight and 10% by weight or less, based on the total monomers. When this range is satisfied, the bending resistance and the adhesive force of the impact absorbing layer can be improved.
The copolymerizable monomer may be, for example, one monomer selected from the group consisting of styrene, α -methylstyrene, vinyltoluene, t-butylstyrene, 1, 3-dimethylstyrene, 2, 4-dimethylstyrene, ethylstyrene, and a combination of two or more monomers thereof, but the present application is not limited thereto. The copolymerizable monomer is contained in an amount of 0.01 to 10% by weight based on the total monomers. When this range is satisfied, the bending resistance and the adhesive force of the impact absorbing layer can be improved.
According to a specific embodiment, the first acrylic copolymer may be obtained by adding a solvent to the monomer mixture and causing a reaction by adding an initiator.
The solvent may be, for example, one solvent selected from the group consisting of ethyl acetate, n-pentane, isopentane, neopentane, n-hexane, n-octane, n-heptane, methyl ethyl ketone, acetone, toluene, and a combination of two or more thereof, but the present application is not limited thereto. The solvent may be used in an amount of 10 to 30 parts by weight, for example, 15 to 25 parts by weight, based on 100 parts by weight of the monomer mixture.
Examples of initiators may include: azo compounds such as Azobisisobutyronitrile (AIBN), 2' -azobis (2-methylbutyronitrile), and azobiscyanovaleric acid; organic peroxides such as t-butyl peroxypivalate, t-butyl peroxybenzoate, t-butyl peroxy-2-ethylhexanoate, di-t-butyl peroxide, cumene hydroperoxide, benzoyl peroxide, and t-butyl hydroperoxide; and inorganic peroxides such as hydrogen peroxide, ammonium persulfate, potassium persulfate, and sodium persulfate. Exemplary initiators may be used alone or in combinations of two or more of them. The initiator may be used in an amount of 0.005 to 0.1 parts by weight, based on 100 parts by weight of the monomer mixture. When this range is satisfied, the monomers can be reacted efficiently.
The glass transition temperature of the elasticity-imparting resin measured by a DSC thermal analysis method is greater than-20 ℃ and not greater than 20 ℃. When this range is satisfied, the elasticity imparts the resin with the effects of excellent adhesive strength and high impact absorption. When the glass transition temperature of the elasticity-imparting resin is-20 ℃ or lower, there is a problem of a decrease in elasticity, and when the glass transition temperature of the elasticity-imparting resin is more than 20 ℃, there is a problem of a decrease in durability. Preferably, the glass transition temperature of the elasticity imparting resin is greater than-20 ℃ and 15 ℃ or less, for example, greater than-15 ℃ and 15 ℃ or less.
As the elasticity imparting resin, one or more selected from natural rubber, butadiene-based rubber, chloroprene rubber, Isobutylene Isoprene Rubber (IIR), ethylene-propylene terpolymer (EPDM), chlorosulfonated polyethylene rubber (CSM), and the like may be used, and for example, one or more selected from second acrylic copolymer, butadiene-based rubber, and acrylic rubber may be used. When necessary, a plasticizer or a curing agent may be added to adjust the glass transition temperature of the elasticity-imparting resin.
The second acrylic copolymer may comprise 65 to 80 wt% of units derived from a C1-C12 linear or branched alkyl (meth) acrylate monomer, 5 to 25 wt% of units derived from a C6-C20 cycloaliphatic alkyl (meth) acrylate monomer, 0.05 to 10 wt% of units derived from a hydroxyl-containing (meth) acrylate monomer, and 0.01 to 10 wt% of units derived from a copolymerizable monomer.
Examples of the C1-C20 linear or branched alkyl (meth) acrylate monomer may include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, butyl (meth) acrylate, pentyl (meth) acrylate, hexyl (meth) acrylate, octyl (meth) acrylate, nonyl (meth) acrylate, decyl (meth) acrylate, undecyl (meth) acrylate, dodecyl (meth) acrylate, isododecyl (meth) acrylate, tetradecyl (meth) acrylate, pentadecyl (meth) acrylate, hexadecyl (meth) acrylate, heptadecyl (meth) acrylate, octadecyl (meth) acrylate, nonadecyl (meth) acrylate, and the like, but the present application is not limited thereto. Exemplary C1-C20 linear or branched alkyl (meth) acrylate monomers can be used alone or in combinations of two or more of them. Preferably, isododecyl (meth) acrylate may account for 50% by weight or more among the C1-C20 linear or branched alkyl (meth) acrylates, and when this range is satisfied, the bending resistance of the impact absorbing layer may be improved.
Examples of the C6-C20 alicyclic alkyl (meth) acrylate monomer may include isobornyl (meth) acrylate, norbornyl (meth) acrylate, adamantyl (meth) acrylate, 2-methyl-2-norbornyl (meth) acrylate, 2-ethyl-2-norbornyl (meth) acrylate, 2-methyl-2-isobornyl (meth) acrylate, 2-ethyl-isobornyl (meth) acrylate, t-butoxycarbonyl (meth) acrylate, t-butoxycarbonylmethyl (meth) acrylate, and the like, but the present application is not limited thereto. Exemplary C6-C20 cycloaliphatic alkyl (meth) acrylate monomers can be used alone or in combinations of two or more of them. Preferably, isobornyl (meth) acrylate may account for 50% by weight or more in the C6-C20 alicyclic alkyl (meth) acrylate monomer, and when this range is satisfied, the bending resistance of the impact absorbing layer may be improved.
Examples of the hydroxyl group-containing (meth) acrylate monomer may include a (meth) acrylate having one or more hydroxyl groups. For example, the hydroxyl group-containing (meth) acrylate may be one or more selected from the group consisting of: 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, 1, 4-cyclohexanedimethanol mono (meth) acrylate, 1-chloro-2-hydroxypropyl (meth) acrylate, diethylene glycol mono (meth) acrylate, 1, 6-hexanediol mono (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol penta (meth) acrylate, neopentyl glycol mono (meth) acrylate, trimethylolpropane di (meth) acrylate, trimethylolethane di (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, glycidyl (meth) acrylate, and the like, 4-hydroxycyclopentyl (meth) acrylate, 4-hydroxycyclohexyl (meth) acrylate, and cyclohexanedimethanol mono (meth) acrylate. Preferably, the hydroxyl group-containing (meth) acrylate is one of (meth) acrylates including a C2-C4 alkyl group having one or more hydroxyl groups, such as 2-hydroxyethyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, and 4-hydroxybutyl (meth) acrylate, or a combination of two or more thereof. The hydroxyl group-containing (meth) acrylate monomer is contained in an amount of 5 to 20% by weight, for example, more than 5% by weight and 15% by weight or less, based on the total monomers. When this range is satisfied, the bending resistance and the adhesive force of the impact absorbing layer can be improved.
The copolymerizable monomer may be, for example, styrene, alpha-methylstyrene, vinyltoluene, t-butylstyrene, 1, 3-dimethylstyrene, 2, 4-dimethylstyrene, ethylstyrene, and a combination of two or more monomers thereof, but the present application is not limited thereto. The copolymerizable monomer is contained in an amount of 0.5 to 10% by weight, for example 1 to 5% by weight, based on the total monomers. When this range is satisfied, the bending resistance and the adhesive force of the impact absorbing layer can be improved.
According to a particular embodiment, the second acrylic copolymer may be obtained by adding a solvent to the monomer mixture and causing a reaction by adding an initiator.
The solvent may be, for example, one solvent selected from the group consisting of ethyl acetate, n-pentane, isopentane, neopentane, n-hexane, n-octane, n-heptane, methyl ethyl ketone, acetone, toluene, and a combination of two or more thereof, but the present application is not limited thereto. The solvent may be used in an amount of 10 to 40 parts by weight, for example, 20 to 30 parts by weight, based on 100 parts by weight of the monomer mixture.
Examples of initiators may include: azo compounds such as AIBN, 2' -azobis (2-methylbutyronitrile) and azobiscyanovaleric acid; organic peroxides such as t-butyl peroxypivalate, t-butyl peroxybenzoate, t-butyl peroxy-2-ethylhexanoate, di-t-butyl peroxide, cumene hydroperoxide, benzoyl peroxide, and t-butyl hydroperoxide; and inorganic peroxides such as hydrogen peroxide, ammonium persulfate, potassium persulfate, and sodium persulfate. Exemplary initiators may be used alone or in combinations of two or more of them. The initiator may be used in an amount of 0.005 to 0.1 parts by weight, based on 100 parts by weight of the monomer mixture. When this range is satisfied, the monomers can be reacted efficiently.
Examples of the butadiene-based rubber may include styrene-butadiene rubber (SBR), polybutadiene rubber (BR), nitrile-butadiene rubber (NBR), and the like, and as the acrylic rubber, commercially available acrylic rubber from Zeon Corporation, DuPont, and the like may be used. For example, an elasticity-imparting resin having an appropriate glass transition temperature can be prepared by mixing nitrile rubber (molecular weight: 236,000; Zeon Corporation) or PA404N (molecular weight: 365,000; Unimatec) with a curing agent.
The first acrylic copolymer and the elasticity imparting resin form a continuous phase. According to a specific embodiment, the continuous phase may be obtained by mixing the first acrylic copolymer and the elasticity imparting resin in a weight ratio of 1.2:1 to 3:1, preferably 1.3:1 to 2:1, more preferably 1.4:1 to 1.8: 1. When this range is satisfied, there is an advantage that a continuous phase having excellent adhesive strength and bending resistance can be formed.
Dispersed phase
The dispersed phase is dispersed in the continuous phase and comprises opacifying particles.
As the light-shielding particles, carbon black, pigments, Ultraviolet (UV) light stabilizers, inorganic particles, and the like can be used. Exemplary opacifying particles can be used alone or in a combination of two or more of them.
The average particle diameter of the light-shielding particles may be 1 μm or less, and is preferably 0.5 μm or less. When this range is satisfied, sufficient light-shielding properties can be obtained.
The light-shielding particles may be used in an amount of 0.1 to 10 parts by weight, based on 100 parts by weight of the mixed resin of the first acrylic copolymer and the elasticity imparting resin. When this range is satisfied, sufficient light-shielding property and conductivity can be obtained, and at the same time, generation of high cost can be avoided.
Adhesive impact absorbing layer
A curing agent, a defoaming agent, and light-shielding particles are added to the mixed resin of the first acrylic copolymer and the elasticity-imparting resin, thereby obtaining a liquid adhesive formulation. An adhesive impact absorbing layer is formed by preparing the liquid adhesive formulation, forming a coating layer on a substrate using the liquid adhesive formulation, and curing the coating layer.
As the curing agent, isocyanate compounds, epoxy compounds, aziridine compounds, amine compounds, hydrazine compounds, and the like can be used, but the present application is not limited thereto. The curing agent may be used in an amount of 0.1 to 10 parts by weight, based on 100 parts by weight of the mixed resin of the first acrylic copolymer and the elasticity imparting resin. When this range is satisfied, the phase separation phenomenon and the like can be suppressed.
As the defoaming agent, any material for improving the coating property or phenomenon, such as propylene oxide-ethylene oxide surfactant (PES), sodium dinaphthalenedisulfonate surfactant, polyoxyethylene octylphenyl ether, may be used, but the present application is not limited thereto. The antifoaming agent may be used in an amount of 0.1 to 10 parts by weight, based on 100 parts by weight of the mixed resin of the first acrylic copolymer and the elasticity imparting resin. When this range is satisfied, the coating layer property or phenomenon can be improved without adversely affecting the adhesive strength.
The adhesive impact absorbing layer has a CFD of 0.10 to 0.25MPa, and preferably more than 0.15 to less than 0.25MPa, under 25% compression, and a CFD of 0.3 to 0.5MPa, and preferably 0.4 to less than 0.5MPa, under 50% compression, and has an impact absorption rate of 40 to 60%, preferably more than 40 to less than 60%, and more preferably 45 to 50%, as measured by a ball drop test performed by dropping 13.8g balls from a height of 10 cm.
The adhesive impact absorbing layer has an adhesive strength of more than 2,000gf/in and 5,500gf/in, and preferably 2,500gf/in to 5,000gf/in, for example 3,000gf/in to 4,000gf/in, under conditions of a temperature of 23 ± 2 ℃ and a relative humidity of 50 ± 5%, when measured by stretching at a rate of 300 ± 30mm/min, and an adhesive strength of 500gf/in to 2,000gf/in, and preferably more than 1,000gf/in and 2,000gf/in, for example 1,100gf/in to 1,500gf/in, under conditions of a temperature of 85 ± 2 ℃ and a relative humidity of 50 ± 5%, when measured by stretching at a rate of 300 ± 30 mm/min.
The adhesive force of the adhesive impact absorbing layer to the substrate is 1,900gf/in to 3,000gf/in under the condition that the temperature is 23 + -2 ℃ and the relative humidity is 50 + -5%, for example, 2,100gf/in to 2,600gf/in, when measured by stretching at a rate of 300 + -30 mm/min, and preferably greater than 2,000gf/in and equal to or less than 3,000gf/in, and the adhesive force of the adhesive impact absorbing layer to the substrate is 600gf/in to 1,300gf/in, and preferably greater than 1,000gf/in and less than 1,300gf/in, for example, 1,100gf/in to 1,200gf/in, under the condition that the temperature is 85 + -2 ℃ and the relative humidity is 50 + -5%, when measured by stretching at the same rate.
The adhesive impact absorbing layer satisfies the following formula 1:
[ formula 1]
2.0≤CFD50/CFD25≤3.0
In formula 1, CFD50 is CFD (mpa) measured at 50% of the initial thickness, and CFD25 is CFD (mpa) measured at 25% of the initial thickness, CFD (mpa) being measured by: a 10mm thick sample was prepared by stacking and pressing the material at a rate of 400mm/min and a load of 4kg using an automatic press roll, and the sample was pressed by lowering the upper plate at a rate of 5mm/min towards a load cell of 1kN using UTM. When the CFD50/CFD25 ratio satisfies the above range, it is possible to absorb the impact and at the same time exhibit an appropriate repulsive force. When the CFD50/CFD25 ratio of the impact absorbing layer is greater than 3.0, the manufactured impact absorbing layer may be lifted due to a low recovery rate, and cannot sufficiently absorb an impact due to an excessively long recovery time in an environment where a small impact is often applied to the impact absorbing layer. On the other hand, when the CFD50/CFD25 ratio of the impact absorbing layer is less than 2.0, the repulsive force becomes too large at some compression points, making it impossible to absorb the impact.
The adhesive impact absorbing layer has a CS of 90% or more, an Rz surface roughness (average roughness of 10 points) of 0.5 to 50 μm, preferably 0.6 to 25 μm, and most preferably 0.7 to 10 μm, and an Ra surface roughness (average centerline roughness) of 0.01 to 0.4 μm, preferably 0.03 to 0.2 μm, and most preferably 0.06 to 0.1 μm. The lower the roughness of the surface of the adhesive absorption layer, the flatter the surface, and thus the higher the adhesiveness of the surface.
Meanwhile, the density of the adhesive impact absorbing layer, which is represented by the proportion of the unit area occupied by the adhesive impact absorbing layer, ranges from 0.7 to 1, preferably from 0.8 to 1, and more preferably from 0.9 to 1. Since a higher density means that the number of bubbles formed in the adhesive impact absorbing layer is small and the area occupied by the bubbles is small, the surface adhesive strength for a given area can be improved and the impact absorption rate of the impact absorbing layer can be increased.
The adhesive impact absorbing layer may be suitably applied to the surface of the substrate in order to impart excellent impact absorbing property and adhesive force. For example, the adhesive impact absorbing layer may be directly adhered to a polyimide film for a mobile device or an ultra-thin electronic device without an intervening adhesive, and impart excellent impact absorbing properties and excellent adhesive strength.
Since the adhesive impact absorbing layer has not only impact absorbing properties but also adhesive force, the adhesive impact absorbing layer can be directly adhered to the polyimide film without any intervening adhesive layer.
Laminated body
Yet another aspect of the present application provides a laminate. The laminate has a structure in which the adhesive impact absorbing layer, the polyimide film, and the light-shielding layer are stacked in this order. Referring to fig. 2, which is a cross-sectional view showing a cross-section of a laminate according to one embodiment of the present application, an adhesive impact absorbing layer 110, a polyimide film 120, and a light shielding layer 130 are sequentially stacked, and the adhesive impact absorbing layer 110 may be directly adhered to the polyimide film 120 without any adhesive or adhesive layer interposed therebetween. Therefore, the method for manufacturing a laminate of the present application has improved efficiency and improved economic efficiency.
As the polyimide film, any type of commercially available polyimide film having a thickness of 25 μm to 225 μm, for example, may be used
Figure BDA0002737552430000131
(DuPont)。
The light-shielding layer may be formed by mixing 20 to 30 wt% of a binder, 60 to 70 wt% of a solvent, and 8 to 15 wt% of light-shielding particles, applying the mixture to a polyimide film, and drying the mixture. When dried, the thickness of the light-shielding layer may be 10 μm or more, and is preferably more than 10 μm.
The laminate can be obtained by applying an adhesive impact absorbing layer onto the surface of the polyimide film opposite to the surface coated with the light-shielding layer using, for example, a roll or a comma coater, moving the resultant into a drying oven, and drying the resultant at a temperature of 60 ℃ for 48 hours.
Hereinafter, the configuration and operation of the present application will be described in more detail through exemplary embodiments of the present application. However, the exemplary embodiments are merely illustrative of the present application and should not be construed as limiting the present application in any way.
Since those skilled in the art can technically deduce details not described herein, the description of such details will be omitted.
Examples
The technical parameters of the components used in the following examples and comparative examples are as follows:
(A) first acrylic copolymer
To an 80 wt% monomer mixture prepared by mixing 37 wt% of 2-ethylhexyl acrylate, 17 wt% of n-butyl methacrylate, 17 wt% of ethyl acrylate, 7 wt% of 2-hydroxyethyl methacrylate, and 2 wt% of styrene, 20 wt% of ethyl acetate was added. A first acrylic copolymer having a glass transition temperature of-40 ℃ was obtained by adding 0.01 parts by weight of AIBN as an initiator to 100 parts by weight of a mixture of a monomer mixture and ethyl acetate, causing a reaction and conducting the reaction at about 50 ℃ for two hours and at 75 ℃ for 10 hours.
(B) Elasticity-imparting resin
(B1) First elasticity imparting resin
Nitrile rubber (molecular weight: 236,000; Zeon Corporation) was dissolved in methyl ethyl ketone solvent at 70 ℃ for 24 hours while stirring, to thereby obtain an elasticity-imparting resin having a solid content of 20%.
(B2) Second elasticity-imparting resin
PA404N acrylic rubber (molecular weight: 365,000; Unimatec) was dissolved in methyl ethyl ketone solvent at 70 ℃ for 24 hours while stirring, to thereby obtain an elasticity-imparting resin having a solid content of 20%.
(B3) Second acrylic copolymer
45% by weight of isododecyl acrylate, 11.1% by weight of isobornyl methacrylate, 11.1% by weight of ethyl acrylate, 8% by weight of 2-hydroxyethyl methacrylate and 2.3% by weight of styrene were mixed, and 22.5% by weight of ethyl acetate was added to the mixture. By adding 0.01 parts by weight of AIBN as an initiator to 100 parts by weight of a mixture of the monomer mixture and ethyl acetate, a reaction was caused and carried out at about 50 ℃ for two hours and at 75 ℃ for 10 hours, thereby obtaining a second acrylic copolymer having a glass transition temperature of 10 ℃.
(B4) Hollow particle (Matsumoto M-7)
(B5) PA404N acrylic rubber (molecular weight: 365,000; Unimatec; Tg: -42 ℃ C.)
(B7) Heat-resistant acrylic adhesive (PA series; Tg: -32 ℃ C.)
Example 1
A mixture was prepared by mixing the first elasticity imparting resin B1 prepared above and the first acrylic copolymer a at a ratio of 6:4 in terms of solid content based on the rubber solution. To the mixture were added 2 parts by weight of an isocyanate curing agent, 2 parts by weight of a black pigment, and 0.2 parts by weight of a BYK333 antifoaming agent, and sufficiently stirred, thereby obtaining a liquid impact absorbing adhesive formulation. Here, the amounts of the respective components are expressed in amounts based on 100 parts by weight of the solid content of the mixed resin.
The liquid adhesive formulation was coated on a polyimide film substrate on a coating line and dried in a drying oven, thereby obtaining an adhesive tape containing an impact absorbing adhesive. Subsequently, the tape was aged at a temperature of 60 ℃ for 48 hours, thereby stabilizing the resin.
Example 2
The same procedure as in example 1 was conducted except that the second elasticity-imparting resin B2 was used in place of the first elasticity-imparting resin B1.
Example 3
The same procedure as in example 1 was conducted, except that the second acrylic copolymer B3 was used in place of the second elasticity-imparting resin B1.
Comparative example 1
The same procedure as in example 1 was conducted except that hollow fine particles (Matsumoto M-7) were used instead of the first elasticity-imparting resin B1. The hollow fine particles (Matsumoto M-7) were added in an amount of 2.5 parts by weight based on 100 parts by weight of the first acrylic copolymer.
Comparative example 2
The same procedure as in example 1 was conducted except that PA404N acrylic rubber B5 (molecular weight: 365,000; Unimatec; Tg: -42 ℃) which is a highly elastic material was used in place of the first acrylic copolymer A and the first elasticity-imparting resin B1 prepared above.
Comparative example 3
A liquid impact-absorbing adhesive formulation was prepared by adding 2 parts by weight of an isocyanate curing agent, 2 parts by weight of a black pigment, and 0.2 parts by weight of a BYK333 antifoaming agent to 100 parts by weight of the mixed resin in the first acrylic copolymer a, and sufficiently stirring.
The prepared liquid formulation was coated on a polyimide film substrate on a coating line and dried in a drying oven, thereby obtaining an adhesive tape containing an impact absorbing adhesive. Subsequently, the tape was aged at a temperature of 60 ℃ for 48 hours, thereby stabilizing the resin.
Comparative example 4
To 100 parts by weight of a heat-resistant acrylic adhesive B7(PA series; H company; Tg: -32 ℃ C.), 0.5 part by weight of an isocyanate curing agent, 10.9 parts by weight of an azodicarbonamide type curing accelerator, and 2 parts by weight of a black pigment were added to prepare a liquid formulation. After adjusting the solid content to 35% and the viscosity to the range of 540cP to 650cP, the liquid formulation was coated on a polyimide film substrate, dried in a drying oven for about 120 minutes, and then aged at 60 ℃ for 72 hours.
Evaluation method
Evaluation of pressure deflection (CFD)
The test was carried out under standard conditions of temperature 23. + -. 2 ℃ and relative humidity 50. + -. 5%. UTM was used as a test instrument, a load cell of 1kN and upper and lower platens of about Φ 98 were used, and automatic rolls having a width of 250mm and a weight of 2kg were used as a pressing apparatus. Here, the UTM should be connectable to a recording system so that displacement and compression loads can be recorded.
To prepare a test specimen, a sample material was cut into a size of 150mm × 300mm, and pressed once at a rate of 400mm/min and a load of 4kg using an automatic press roll so that the thickness became 1mm, and bubbles were removed, and when the product was not suitable for stacking, the product was maintained for 10 minutes and then stacked. The product having a thickness of 1mm was stacked to a total thickness of 10mm, cut again to a size of 25mm × 25mm, and when the cutting was completed, maintained under standard conditions until the cross section in the pressed state was restored, thereby completing the preparation of the test specimen.
The CFD of each sample was measured. The upper and lower press plates were mounted on the UTM, the upper plate was lowered at a rate of 5mm/min and contacted with the lower plate, and the displacement of the time point when the CFD reached 0.02kgf was set as a zero point. Subsequently, after the upper plate was raised and the sample was placed in the center of the lower plate, the upper plate was lowered and brought into contact with the surface of the sample under a press condition of a load cell of 1kN and a rate of 5 mm/min. After setting the point at which the upper plate is in contact with the test specimen and detecting a CFD of 0.02kgf as the initial thickness of the test specimen, the upper plate is lowered under the same pressing conditions, and then maintained for 60 seconds at the point at which the thickness of the test specimen reaches 25% or 50% of the initial thickness of the test specimen, and the CFD is measured.
Evaluation of compression deformation ratio (CS)
The test was carried out under standard conditions of a temperature of 23. + -. 2 ℃ and a relative humidity of 50. + -. 5%, and a dry oven or an air oven, a compression plate and an electronic digital caliper were used as a test device.
For each sample type, three samples having a width of 25mm, a length of 25mm, a height of 10mm, and upper and lower surfaces parallel to each other and perpendicular to the side surfaces were prepared. A test piece having a thickness of less than 10mm was prepared to have a thickness of 10mm by stacking without using an adhesive.
After measuring and recording the initial thickness (to) of the test specimen using an electronic digital caliper, the test specimen is placed in a compression device and, when several test specimens are placed simultaneously, the test specimens are placed at least 6mm apart from each other in each direction. After the sample placed in the compression device was compressed to a range of 50 ± 1%, the compression device with the compressed sample was placed in a dry box within 15 minutes after compression and maintained at 70 ℃ for 22 hours. After a standing time of 22 hours, the specimen was taken out of the compression apparatus and allowed to recover for 30 minutes under standard conditions, the final thickness (tf) of the specimen was measured, and cs (cs) was calculated by the following method. When calculating Cs, in the case of the samples including the substrate, only the thickness remaining after subtracting the substrate thickness from the measured total thickness is used, and the measurement results of the three samples are averaged.
Cs＝[(to–tf)/to]×100
Compression set ratio of Cs
to is the initial specimen thickness
tf-final specimen thickness
Evaluation of impact absorptivity
The test was performed under standard conditions of a temperature of 23. + -. 2 ℃ and a relative humidity of 50. + -. 5%, and an electromagnetic ball-drop tester and an SUS steel ball were used as test devices.
For each sample type, three samples having a width of 30mm, a length of 30mm, a height of the actual article, and upper and lower surfaces parallel to each other were prepared.
The test was carried out by fixing the sample at the center of an electromagnetic ball drop test machine, fixing a steel ball at a position 10cm from the ground, dropping the ball on the sample without rotating, and calculating the impact absorption rate using the measured impact amount as follows.
(S) impact absorption rate [% ]0–S1)/S0×100％
S0Amount of impact measured without sample
S1Amount of impact applied to the test piece
Evaluation of adhesive Strength (peeling Strength)
Evaluation at room temperature
A sample having a width of 25mm and a length of 200mm was prepared, laminated on an SUS304 steel plate, subjected to one round-trip pressing at a rate of 25mm/sec by using a 2kg roller, and maintained under standard conditions of a temperature of 23 ± 2 ℃ and a relative humidity of 50 ± 5% for 30 minutes.
The average strength (in gf/in) was measured while stretching one side of the laminated test piece at an angle of 180 ° to the lamination direction, i.e., in the direction opposite to the lamination direction, at a rate of 300 ± 30 mm/min. Three to five determinations were made for each sample, and their average value was calculated.
Evaluation at high temperature
The samples were laminated and pressed in the same manner, and then maintained for 30 minutes under conditions of a temperature of 85 ℃ and a relative humidity of 50 ± 5%, and the adhesive strength of each sample was measured three to five times by stretching the sample in the same manner, and the average value thereof was calculated.
Evaluation of adhesion to substrate
Evaluation at room temperature
After preparing a sample having a width of 25mm and a length of 200mm, a double-sided tape having the same size as the sample was adhered to a SUS304 steel plate. Subsequently, the sample was adhered to a double-sided tape, subjected to one round-trip pressing at a rate of 25mm/sec using a 2kg roller, and then maintained under standard conditions of a temperature of 23 ± 2 ℃ and a relative humidity of 50 ± 5% for 30 minutes.
The adhesion (in gf/in) was measured while stretching the adhered specimen at an angle of 180 ° to the lamination direction, i.e., in the direction opposite to the lamination direction, at a rate of 300 ± 30 mm/min. Three to five determinations were made for each sample, and their average value was calculated.
Evaluation at high temperature
The test pieces were laminated and pressed in the same manner, and then maintained under conditions of a temperature of 85 ℃ and a relative humidity of 50 ± 5% for 30 minutes, and in the same manner, the adhesion force of each test piece to the substrate was measured three to five times, and the average value thereof was calculated.
Evaluation of the surface
Evaluation of surface Density
The width, length and height of the prepared product are all 10mm, and the volume is 1cm3And calculating the true density of the sample. By measuring the weight (W) of the sample in airAir (a)) The sample was completely immersed in a beaker of water containing 2/3 and the contents of the beaker were measured using a gravimetric instrument (SD-200L; CAS Korea co., Ltd.) weight of the samples in water (W) was measuredWater (W)) And W isAir (a)And WWater (W)The true density is calculated by substituting the following equation.
True density＝WAir (a)/(WAir (a)-WWater (W))
The results of the above evaluations are shown in table 1 below.
Figure BDA0002737552430000201
Referring to table 1, it can be seen that comparative examples 1 and 2 have satisfactory CFD and CS, but are not suitable as impact absorbing layers due to their low impact absorption rate, low adhesion to substrates, and low adhesive strength.
It can be seen that comparative example 3 has not only significantly lower CFD and CS than other comparative examples or examples, but also low adhesive force to the substrate and low adhesive strength at high temperature, and thus is not suitable as an impact absorbing layer. It can be seen that comparative example 4 has relatively high adhesion to the substrate at room temperature and relatively high adhesive strength, but the adhesion to the substrate and the adhesive strength at high temperature are significantly reduced, and the impact absorption rate, CS, and CFD are not sufficiently high, and thus are not suitable as an impact absorbing material, as compared to other comparative examples.
On the other hand, it can be seen that examples 1 to 3 have excellent adhesive force to the substrate at both room temperature and high temperature and have excellent adhesive strength, and thus can be stably used in various environments, and from their CFD, CS and impact absorption rate, it can be confirmed that examples 1 to 3 have high bending resistance against external physical impact.
Evaluation of surface roughness
For the samples of example 1, commercially available low-density foam (NC1122FA 05; Anyone Inc.) and high-density foam (FS 1250; Mainelecom co., Ltd.) were prepared to have a width of 25mm and a length of 200mm, and Rz and Ra were measured by irradiating a non-contact laser in longitudinal and transverse directions with respect to a center point of each sample and measuring reflectance values using a roughness measurement tester (NV-2700; NanoSystem co., Ltd.).
[ Table 2]
Test specimen Rz(μm) Ra(μm)
Low density foam tape 313.99 7.19
High density foam adhesive tape 67.18 0.48
Example 1 1.27 0.08
Referring to table 2, it can be seen that example 1 of the present application has a low surface roughness, compared to commercially available impact absorbing tapes having a high surface roughness. Therefore, it can be expected that example 1 will have excellent adhesion to a substrate and adhesive strength, and thus can be stably used in various environments.
According to the present application, there can be provided: an adhesive impact absorbing layer having improved adhesion to a substrate at high and room temperatures while having excellent bending resistance, being directly adhered to a polyimide film without any intervening adhesive layer, having high CFD even without including foam particles, having excellent surface roughness, having high CS stability due to optimized heat resistance and fluidity, having improved process simplicity and article reliability, and being suitable for use in an adhesive film tape; and a laminate comprising the adhesive impact absorbing layer.

Claims (11)

1. An adhesive impact absorbing layer comprising:
a continuous phase; and
a dispersed phase dispersed in the continuous phase,
wherein the continuous phase comprises a first acrylic copolymer having a glass transition temperature of-50 ℃ to-20 ℃ and an elasticity-imparting resin, and the dispersed phase comprises light-screening particles.
2. The adhesive impact-absorbing layer according to claim 1, wherein the elasticity-imparting resin comprises one or more selected from the group consisting of a second acrylic copolymer having a glass transition temperature of more than-20 ℃ and 20 ℃ or less, a butadiene-based rubber, and an acrylic rubber.
3. The adhesive impact-absorbing layer according to claim 1, wherein the weight ratio of the first acrylic copolymer and the elasticity-imparting resin ranges from 1.2:1 to 3: 1.
4. The adhesive impact-absorbing layer of claim 1, wherein the opacifying particles comprise at least one of carbon black, black pigment, and color pigment.
5. The adhesive impact absorbing layer of claim 1, having:
a pressure deflection (CFD) of 0.10MPa to 0.25MPa at 25% compression and 0.3MPa to 0.5MPa at 50% compression;
an impact absorption rate of 40% or more as measured by a ball drop test in which 13.8g of balls are dropped from a height of 10 cm;
an adhesive strength of more than 2,000gf/in under the conditions of a temperature of 23 + -2 ℃ and a relative humidity of 50 + -5% and an adhesive strength of 500gf/in or more under the conditions of a temperature of 85 + -2 ℃ and a relative humidity of 50 + -5% when measured by drawing at a rate of 300 + -30 mm/min; and is
The adhesive impact absorbing layer has an adhesive force to the substrate of 1,900gf/in or more under the conditions of a temperature of 23 + -2 ℃ and a relative humidity of 50 + -5% when measured by stretching at a rate of 300 + -30 mm/min, and has an adhesive force to the substrate of 600gf/in or more under the conditions of a temperature of 85 + -2 ℃ and a relative humidity of 50 + -5%.
6. The adhesive impact-absorbing layer according to claim 1, satisfying the following formula 1:
[ formula 1]
2.0≤CFD50/CFD25≤3.0，
Wherein, in formula 1, CFD50 is the pressure deflection (CFD) (MPa) measured at 50% of the initial thickness, and CFD25 is the CFD (MPa) measured at 25% of the initial thickness, the CFD (MPa) being determined by: a 10mm thick sample was prepared by stacking sample materials and pressing the materials at a rate of 400mm/min and a load of 4kg using an automatic compression roller, and pressing the sample by lowering the upper plate toward a load cell of 1kN using a universal tester at a rate of 5 mm/min.
7. The adhesive impact-absorbing layer according to claim 1, having a density of 0.90 or more and less than 1.0 and a Compression Set (CS) of 90% or more.
8. The adhesive impact-absorbing layer according to claim 1, having an Rz surface roughness of 0.5 to 50 μ ι η and an Ra surface roughness of 0.01 to 0.4 μ ι η.
9. The adhesive impact-absorbing layer according to claim 1, having a thickness of 40 to 150 μm.
10. A laminate in which the adhesive impact absorbing layer according to any one of claims 1 to 9, a polyimide film, and a light shielding layer are stacked in this order.
11. The laminate of claim 10, wherein the polyimide film is in direct contact with the adhesive impact absorbing layer without an intervening adhesive layer.
CN202011138611.4A 2019-10-22 2020-10-22 Adhesive impact absorbing layer and laminate comprising same Pending CN112694843A (en)

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JP6343836B2 (en) * 2013-10-31 2018-06-20 藤森工業株式会社 Light diffusion adhesive layer and light diffusion adhesive film
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Publication number Priority date Publication date Assignee Title
CN1047324A (en) * 1989-05-16 1990-11-28 罗姆和哈斯公司 The propylene ester adhesive composition that contains linking agent and impact modifying agent
JP2006010931A (en) * 2004-06-24 2006-01-12 Dainippon Ink & Chem Inc Double-coated tape and liquid crystal display module unit using same
CN1993440A (en) * 2005-04-13 2007-07-04 Lg化学株式会社 Acrylic adhesive composition having excellent impact resistance, optical film using the adhesive composition, and liquid crystal display comprising the optical film
CN103666295A (en) * 2012-09-06 2014-03-26 日东电工株式会社 Double-sided pressure-sensitive adhesive sheet
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