CN113480936B

CN113480936B - Solvent-free coating and preparation method thereof

Info

Publication number: CN113480936B
Application number: CN202110758391.3A
Authority: CN
Inventors: 赵涛; 王志鑫; 李勇; 桑莹莹; 裴道海; 李金钟
Original assignee: ASIA PAINT (SHANGHAI) CO LTD
Current assignee: ASIA PAINT (SHANGHAI) CO LTD
Priority date: 2021-07-05
Filing date: 2021-07-05
Publication date: 2022-07-08
Anticipated expiration: 2041-07-05
Also published as: CN113480936A

Abstract

The invention relates to the technical field of coatings, in particular to a solvent-free coating and a preparation method thereof. The solvent-free coating comprises the following components in parts by weight: 20-40 parts of hydroxyl-terminated polysiloxane; 5-10 parts of dimethyl diethoxy silane oligomer; 2-8 parts of a cross-linking agent; 0.1-6 parts of a functional assistant; 30-60 parts of a filler; the viscosity of the hydroxyl-terminated polysiloxane at 23 ℃ is 400-1500 mPa.s, and the average polymerization degree n of the dimethyl diethoxy silane oligomer is 9-11. It has the excellent performances of stable coating formula, flexible coating, aging resistance, cracking resistance, moisture resistance, hydrophobicity and the like.

Description

Solvent-free coating and preparation method thereof

Technical Field

The invention relates to the technical field of coatings, in particular to a solvent-free coating and a preparation method thereof.

Background

With the development of economy and the improvement of the living standard of people, the coating serves as an essential living material and plays an irreplaceable role in the aspects of military industry, aerospace, civil daily use chemicals and the like. Meanwhile, the coating also commonly contains various volatile solvents, which causes serious environmental pollution and serious harm to the health of people. In view of the fact that the building coating mainly plays a role in decoration and protection of buildings, has a huge application market, and in order to avoid high pollution caused by solvent-based coatings, people develop water-based coatings or solvent-free coatings to replace oil-based coatings for buildings, and the solvent-free building coatings and the water-based building coatings are leading the development trend of the decorative material market.

The water-based paint is a kind of synthetic resin emulsion paint, generally takes water as a dispersion medium, has the characteristics of relative environmental protection and good color retention, and the water-based product is taken as a market leading product in most of the building paints. However, some current water-based coatings have the problems of poor aging resistance, easy contamination, poor scrub resistance, poor elasticity, cracking resistance, no hydrophobicity, VOC emission and the like.

The solvent-free coating does not discharge VOC (volatile organic compounds) into the atmosphere in the process of curing and film forming, has more excellent performance than a water-based coating, and will be used in the future. After being consulted, one technical scheme is as follows: the nano modified polysiloxane oligomer is added into the solvent-free coating, and the ionic liquid and the conductive filler are added to realize excellent electrostatic conductivity of the coating, so that the defects of cracking of the coating, reduction of mechanical properties, reduction of adhesive force, water and air permeability, reduction of corrosion resistance and the like are avoided. However, the formulation has poor stability and requires a complicated preparation process of the nano-modified polysiloxane oligomer. The other technical scheme is as follows: two kinds of organic silicon polysiloxane with different viscosities are compounded, so that the weather resistance and the decorative performance of the coating are improved. But the formed film layer becomes hard and brittle with time.

Disclosure of Invention

Based on the solvent-free coating, the invention provides the solvent-free coating which has the excellent properties of stable coating formula, flexible coating, aging resistance, cracking resistance, moisture resistance, hydrophobicity and the like.

The technical scheme is as follows:

the solvent-free coating comprises the following components in parts by weight:

the hydroxyl-terminated polysiloxane has a viscosity of 400 to 1500mpa.s at 23 ℃;

the average polymerization degree n of the dimethyl diethoxy silane oligomer is 9-11.

In one embodiment, the solvent-free coating comprises, in parts by weight:

in one embodiment, the dimethyldiethoxysilane oligomer has a viscosity of from 8 to 10mPa.s at 23 ℃.

In one embodiment, the cross-linking agent is methyltripropoximinosilane.

In one embodiment, the functional additives include promoters, catalysts, and coupling agents.

In one embodiment, the promoter is dibutyl tin diacetate.

In one embodiment, the catalyst is dibutyltin dilaurate.

In one embodiment, the functional auxiliary agent further comprises one or more of polytetrafluoroethylene micro powder, a moisture-proof and mildew-proof agent and a pigment.

In one embodiment, the filler comprises one or more of fumed silica, nano calcium carbonate, titanium dioxide, wollastonite powder, talcum powder, mica powder and silica micropowder.

In one embodiment, the filler is a combination of fumed silica, nano calcium carbonate and wollastonite powder.

In one embodiment, the filler is a combination of fumed silica, nano calcium carbonate, wollastonite powder and titanium dioxide.

In one embodiment, the filler is a combination of fumed silica, nano calcium carbonate, wollastonite powder and a filler, and the filler is at least one of talcum powder, mica powder and silica powder.

In one embodiment, the filler is a combination of fumed silica, nano calcium carbonate, wollastonite powder, titanium dioxide and a filler, and the filler is at least one of talcum powder, mica powder and silica powder.

In one embodiment, the solvent-free coating comprises, in parts by weight:

the invention also provides a preparation method of the solvent-free coating.

The preparation method of the solvent-free coating comprises the following steps:

mixing hydroxyl-terminated polysiloxane, filler and a part of functional auxiliary agent, and stirring to prepare slurry;

and mixing the slurry, the cross-linking agent, the dimethyl diethoxy silane oligomer and the residual functional auxiliary agent, and stirring to prepare the solvent-free coating.

Compared with the prior art, the invention has the following beneficial effects:

in the solvent-free coating, hydroxyl-terminated polysiloxane with the viscosity of 400-1500 mPa.s at 23 ℃ is used as a main film forming substance, the coating can realize crosslinking curing under the action of a crosslinking agent and a functional assistant, and simultaneously, the dimethyl diethoxy silane oligomer is added in a matching manner, can participate in a film forming reaction in the crosslinking curing process, increases the length of a chain, can obviously improve the flexibility of the coating compared with other silane oligomers, is not easy to crack in the later period, can keep the coating to have extremely low construction viscosity after being added, does not need to add a solvent, and is easy to construct. Furthermore, the silicone polysiloxane with Si-O-Si main chain has the bond energy of Si-O bond of 121 Kcal/gram molecule, so that the product using the polysiloxane as the basic polymer has high thermal stability, the chemical bond of the molecule is not broken and decomposed at high temperature (or radiation irradiation), and the polysiloxane main chain has no double bond, so that the polysiloxane is not easily decomposed by ultraviolet light and ozone, thereby having excellent weather resistance. The solvent-free coating has good adhesive force on various substrates, and the adhesive force can reach level 1; the water resistance is excellent, and the foaming and the falling are avoided within 96 hours; the tensile strength is high and reaches 2 MPa; the elongation at break is high and can exceed 200 percent; the hydrophobicity is strong, and the water contact angle reaches 125 degrees; the aging resistance is strong, and the ultraviolet light aging resistance reaches 3000h without obvious pulverization and cracking.

Detailed Description

The present invention will be described in further detail with reference to specific examples. The present invention may be embodied in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

Term(s) for

Unless otherwise stated or contradicted, terms or phrases used herein have the following meanings:

as used herein, the term "and/or", "and/or" includes any one of two or more of the associated listed items, as well as any and all combinations of the associated listed items, including any two of the associated listed items, any more of the associated listed items, or all combinations of the associated listed items.

As used herein, "one or more" means any one, any two, or any two or more of the listed items. Wherein, the 'several' means any two or more than any two.

As used herein, "a combination thereof," "any combination thereof," and the like, includes all suitable combinations of any two or more of the listed items.

Herein, "preferred" merely describes a more effective embodiment or example, and it should be understood that the scope of the present invention is not limited thereto.

In the present invention, the technical features described in the open type include a closed technical solution composed of the listed features, and also include an open technical solution including the listed features.

In the present invention, the numerical range is defined to include both end points of the numerical range unless otherwise specified.

The temperature parameter in the present invention is not particularly limited, and may be a constant temperature treatment or a treatment within a certain temperature range. The constant temperature process allows the temperature to fluctuate within the accuracy of the instrument control.

A solvent-free coating comprises the following components in parts by weight:

Hydroxyl-terminated polysiloxane with the viscosity of 400-1500 mPa.s at 23 ℃ is used as a main film forming substance, can realize crosslinking and curing under the action of a crosslinking agent and a functional assistant, and simultaneously, dimethyl diethoxy silane oligomer is added, can participate in a film forming reaction in the crosslinking and curing process, increases the length of a chain, enables a coating to be coated on a base material to form a coating with high flexibility, is not easy to crack in the later period, enables the coating to keep extremely low construction viscosity after being added, does not need to add a solvent, and is easy to construct. Furthermore, the silicone polysiloxane with Si-O-Si main chain has the bond energy of Si-O bond of 121 Kcal/gram molecule, so that the product using the polysiloxane as the basic polymer has high thermal stability, the chemical bond of the molecule is not broken and decomposed at high temperature (or radiation irradiation), and the polysiloxane main chain has no double bond, so that the polysiloxane is not easily decomposed by ultraviolet light and ozone oxygen, thereby having excellent weather resistance.

It will be appreciated that the coatings of the present invention can self cure to form films in air.

In one embodiment, the hydroxyl-terminated polysiloxane can be the 107 gum of the east yue silica.

In one embodiment, the hydroxyl-terminated polysiloxane has a viscosity of 400mpa.s to 800mpa.s at 23 ℃;

optionally, the dimethyldiethoxysilane oligomer has a viscosity of from 8mpa.s to 10mpa.s at 23 ℃. Is beneficial to keeping the coating at a lower construction viscosity and realizing no solvent of the coating.

Preferably, the solvent-free coating comprises, in parts by weight:

preferably, the cross-linking agent is methyltripropioximinosilane.

The hydroxyl-terminated polysiloxane can generate crosslinking curing reaction with the crosslinking agent under the action of a catalyst. The dimethyl diethoxy silane oligomer can participate in film forming reaction under the action of an accelerator to increase the length of a chain.

Preferably, the accelerator is dibutyltin diacetate.

Preferably, the catalyst is dibutyltin dilaurate.

The coupling agent is added, so that the coating and various base materials can be bonded better, the bonding performance of the coating and the base materials is improved, the durability of the performance is kept, and the reaction rate can be improved.

In one embodiment, the coupling agent is a silane coupling agent.

In one embodiment, the coupling agent is KH 550.

Optionally, the functional assistant further comprises one or more of polytetrafluoroethylene micro powder, a moisture-proof and mildew-proof agent and a pigment.

The solvent-free paint can be prepared into varnish, and can also be prepared into colored paint by adding pigment.

At the moment, the pigment is required to be processed into slurry by powder, has good compatibility with other components, is used as a semi-finished product raw material of a formula and is added into a preparation process to prepare a paint product with rich colors and bright colors.

The filler is added, so that the flexibility and compactness of the coating are enhanced.

The filler comprises one or more of fumed silica, nano calcium carbonate, titanium dioxide, wollastonite powder, talcum powder, mica powder and silica micropowder.

Optionally, the filler is a combination of fumed silica, nano calcium carbonate, and wollastonite powder.

Optionally, the filler is a combination of fumed silica, nano calcium carbonate, wollastonite powder and titanium dioxide.

Optionally, the filler is a combination of fumed silica, nano calcium carbonate, wollastonite powder and a filler, and the filler is at least one of talcum powder, mica powder and silica micropowder.

Optionally, the filler is a combination of fumed silica, nano calcium carbonate, wollastonite powder, titanium dioxide and a filler, and the filler is at least one of talcum powder, mica powder and silica powder.

Preferably, the fumed silica is a hydrophobic fumed silica.

Preferably, the nano calcium carbonate has a particle size of 0.01 μm to 0.1. mu.m.

Wherein, hydrophobic fumed silica and nano calcium carbonate are added, which can play a role in molecular reinforcement of the polymer and enhance the flexibility and hydrophobicity of the coating.

Optionally, the hydrophobic fumed silica can be Fuji FT-100, and the nano calcium carbonate can be the active nano calcium carbonate of Garcinia spicata.

Preferably, the titanium dioxide is rutile titanium dioxide.

Preferably, the wollastonite powder is an acicular wollastonite powder.

Further preferably, the length-diameter ratio of the needle-shaped wollastonite powder is (5-15): 1.

Needle-shaped wollastonite powder is added, which can play a filling role on the polymer and effectively enhance the hardness of the coating.

Alternatively, the acicular wollastonite powder can be 3000-mesh acicular wollastonite of Tuopy, Guangzhou.

At least one of talcum powder, mica powder and silica powder is added to enhance the strength of the coating.

The solvent-free coating is a real solvent-free product, and has good adhesive force on various substrates, and the adhesive force can reach level 1; the water resistance is excellent, and the foaming and the falling are avoided within 96 hours; the tensile strength is high and reaches 2 MPa; the elongation at break is high and can exceed 200 percent; the hydrophobicity is strong, and the water contact angle reaches 125 degrees; the aging resistance is strong, and the ultraviolet light aging resistance reaches 3000h without obvious pulverization and cracking.

The solvent-free coating is suitable for decoration of various building interior walls, and has good performance and outstanding effect.

Preferably, the solvent-free coating comprises, in parts by weight:

further preferably, the solvent-free coating comprises, in parts by weight:

Optionally, the stirring rate when preparing the slurry is 1200-1500 r/min.

Alternatively, the stirring rate for preparing the solvent-free coating is 600-800 r/min.

Because the solvent-free coating has less polymer content, powder in the raw materials needs to be prepared into slurry.

It will be appreciated that a portion of the functional agent is a powdered functional agent and that this portion of the functional agent is first prepared as a slurry.

The following examples and comparative examples are further described below, and the starting materials used in the following examples can be commercially available, unless otherwise specified, and the equipment used therein can be commercially available, unless otherwise specified. Specifically, the method comprises the following steps:

the hydroxyl-terminated polysiloxane is 107 glue of Dongye silicon material, wherein the 107 glue has the following viscosity models:

a viscosity of 200mPa.s (23 ℃), a viscosity of 400mPa.s (23 ℃), a viscosity of 800mPa.s (23 ℃) and a viscosity of 1500mPa.s (23 ℃);

the dimethyl diethoxy silane oligomer is a Jiangsu polysilyl oligomer with the viscosity of 8-10 mPa.s at 23 ℃, and the average polymerization degree n is 9-11.

The length-diameter ratio is 5:1, the acicular wollastonite powder is 3000-mesh acicular wollastonite of Guangzhou Tuopy, wherein the 3000-mesh acicular wollastonite has the following length-diameter ratio models:

the length-diameter ratio is 8.5: 1. the length-diameter ratio is 10:1 and aspect ratio of 15: 1.

example 1

The embodiment provides a solvent-free coating and a preparation method thereof, and the solvent-free coating comprises the following steps:

1) preparation of the slurry

Weighing the raw materials according to the weight parts shown in Table 1, mixing hydroxyl-terminated polysiloxane (viscosity at 23 ℃ is 400mpa.s, silicon material in the east Yue), hydrophobic fumed silica, nano calcium carbonate, rutile titanium dioxide, acicular wollastonite powder (length-diameter ratio is 8.5:1, Guangzhou Tuoyi, 3000 meshes), talcum powder and polytetrafluoroethylene micropowder, and stirring at the rotating speed of 1400r/min for 1h to obtain the slurry.

2) Preparation of solvent-free coatings

Mixing the slurry obtained in the step 1), dimethyl diethoxy silane oligomer, an accelerator (dibutyltin diacetate), a catalyst (dibutyltin dilaurate), a crosslinking agent (methyl tripropionoximidosilane), a coupling agent (KH550) and a moisture-proof and mildew-proof agent (zinc pyrithione (ZPT), and stirring at the rotating speed of 700r/min for 0.5h to obtain the solvent-free coating.

3) Performance detection

And (3) performing performance tests on the solvent-free coating obtained in the step 2) by referring to GB/T9756-2018 (superior), JG/T172-2014, GB/T30693-2014 and GB T6739-2006, wherein the results are shown in Table 1.

TABLE 1

Examples 2 to 4

Examples 2-4 all provide a solventless coating and a preparation method thereof, the formula is shown in table 1, the preparation method and the detection method are the same as those of example 1, and the detection results are shown in table 1.

Comparative example 1

Comparative example 1 provides a solvent-free paint and a preparation method thereof, the formulation is shown in table 2, the preparation method and the detection method are the same as those of example 1, and the detection results are shown in table 2.

Wherein 107 gels (200mpa.s) means 107 gels with a viscosity of 200mpa.s at 23 ℃.

TABLE 2

Examples 5 to 6

Examples 5-6 all provide a solventless coating and a method of making the same, the formulation is shown in table 2, the method of making and testing are the same as example 1, and the results are shown in table 2.

Wherein glue 107 (800mpa.s) represents glue 107 having a viscosity of 800mpa.s at 23 ℃;

glue 107 (1500mpa.s) means a glue 107 having a viscosity of 1500mpa.s at 23 ℃.

Examples 7 to 9

Examples 7-9 each provide a solventless coating and its preparation as shown in table 3, the preparation and testing methods are the same as in example 1, and the results are shown in table 3.

Wherein, the acicular wollastonite powder (5.0:1) has an aspect ratio of 5:1 needle-like wollastonite powder; acicular wollastonite powder (8.5:1) has an aspect ratio of 8.5:1 needle-like wollastonite powder;

acicular wollastonite powder (10:1) has an aspect ratio of 10:1 needle-like wollastonite powder;

acicular wollastonite powder (15:1) has an aspect ratio of 15:1 needle-like wollastonite powder.

TABLE 3

Comparative examples 2 to 4

This comparative example provides a solventless coating and a method of preparation thereof, the formulation is shown in table 4, the method of preparation and the method of testing are the same as in example 1, and the results are shown in table 4.

Wherein the dimethyl dimethoxy silane oligomer is Jiangsu polysilyl dimethyl dimethoxy silane oligomer with the viscosity of 8-10 mpa.s at the temperature of 23 ℃, and the average polymerization degree n is 9-11.

The dimethyl dipropoxy silane oligomer is Jiangsu polysilyl dimethyl dipropoxy silane oligomer with the viscosity of 8-10 mpa.s at the temperature of 23 ℃, and the average polymerization degree n is 9-11.

TABLE 4

As can be seen from the above, the solvent-free coatings prepared in examples 1-9 have stable formulations, good adhesion to various substrates, and adhesion up to level 1; the water resistance is excellent, and the foaming and the falling are avoided within 96 hours; the tensile strength is high and reaches 2 MPa; the elongation at break is high and can exceed 200 percent, and the flexibility is good; the hydrophobicity is strong, and the water contact angle reaches 125 degrees; the aging resistance is strong, and the ultraviolet light aging resistance reaches 3000h without obvious pulverization and cracking.

In contrast, in comparative example 1, in which a hydroxyl-terminated polysiloxane having a viscosity of 200mpa.s was used as the main film-forming substance, the tensile strength and elongation at break of the formed coating layer were significantly reduced, and the aging resistance was deteriorated.

In comparative example 2, no dimethyldiethoxysilane oligomer was added, and the formed coating was significantly deteriorated in adhesion, tensile strength, elongation at break, aging resistance, water resistance, alkali resistance, and the like.

In comparative examples 3 and 4, after the dimethyl diethoxysilane oligomer is replaced by the dimethyl dimethoxy silane oligomer and the dimethyl dipropoxysilane oligomer with similar viscosities, the formed coating has poor adhesion, poor water resistance and poor alkali resistance, and the tensile strength and the elongation at break are obviously reduced, and the coating in comparative example 4 does not form a film at a low temperature of 5 ℃.

All possible combinations of the technical features of the above embodiments may not be described for the sake of brevity, but should be considered as within the scope of the present disclosure as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.

Claims

1. The solvent-free paint is characterized by comprising the following components in parts by weight:

20-40 parts of hydroxyl-terminated polysiloxane;

5-10 parts of dimethyl diethoxy silane oligomer;

2-8 parts of a cross-linking agent;

0.1-6 parts of functional auxiliary agent;

30-60 parts of a filler;

the hydroxyl-terminated polysiloxane has a viscosity of 400mPa · s-800mPa · s at 23 ℃;

the average polymerization degree n of the dimethyl diethoxy silane oligomer is 9-11; the dimethyldiethoxysilane oligomer has a viscosity of 8 to 10 mPas at 23 ℃.

2. The solventless coating of claim 1 wherein the crosslinker is methyltripropoximinosilane.

3. The solventless coating of claim 1 wherein the functional additives comprise accelerators, catalysts and coupling agents.

4. A solventless coating according to claim 3 wherein said accelerator is dibutyltin diacetate.

5. The solventless coating of claim 3 wherein the catalyst is dibutyltin dilaurate.

6. The solvent-free paint as claimed in claim 3, wherein the functional assistant further comprises one or more of polytetrafluoroethylene micro powder, a moisture-proof and mildew-proof agent and a pigment.

7. A solventless coating according to any one of claims 1-6 wherein the filler comprises one or more of fumed silica, nano calcium carbonate, titanium dioxide, wollastonite powder, talc, mica powder and silica fume.

8. The solvent-free paint according to claim 7, which comprises the following components in parts by weight:

20-40 parts of hydroxyl-terminated polysiloxane;

5-10 parts of dimethyl diethoxy silane oligomer;

5-10 parts of hydrophobic fumed silica;

0-10 parts of rutile titanium dioxide;

10-20 parts of nano calcium carbonate;

1-5 parts of needle-shaped wollastonite powder;

10-15 parts of talcum powder, mica powder or silicon micropowder;

0-5 parts of polytetrafluoroethylene micro powder;

2-8 parts of a cross-linking agent;

0.1-0.5 part of coupling agent;

0-0.1 part of catalyst;

0-0.1 part of an accelerator;

0.3-0.8 part of antiseptic and mildew inhibitor.

9. A method of preparing a solventless coating according to any one of claims 1 to 8 comprising the steps of: