CN114164703A

CN114164703A - Thermal paper and preparation method thereof

Info

Publication number: CN114164703A
Application number: CN202010948089.XA
Authority: CN
Inventors: 李奕廷; 李吉维; 李娟�; 周晶
Original assignee: GOLD HUASHENG PAPER (SUZHOU INDUSTRIAL PARK) CO LTD
Current assignee: GOLD HUASHENG PAPER (SUZHOU INDUSTRIAL PARK) CO LTD
Priority date: 2020-09-10
Filing date: 2020-09-10
Publication date: 2022-03-11

Abstract

The application provides a thermal paper and a preparation method thereof, wherein the thermal paper comprises: a paper substrate layer; a base coat disposed on the paper substrate; the heat-sensitive layer is arranged on the bottom coating and comprises filler, an adhesive, a color developing agent, a sensitizer, a leuco dye and a lubricant, wherein the filler comprises a high-absorptivity material, the high-absorptivity material is one or a mixture of silica and silicon dioxide, and the silica comprises microparticle silicon dioxide and platy kaolin. The thermosensitive paper provided by the application can provide good printing adaptability while keeping the basic thermosensitive printing performance of the thermosensitive paper, so that the situations of poor printing, virtual image-text and unreal color blocks can be effectively avoided.

Description

Thermal paper and preparation method thereof

Technical Field

The application relates to the technical field of thermal paper, in particular to thermal paper and a preparation method thereof.

Background

The thermal paper is used as a special novel recording material, is different from the traditional recording paper, such as double-sided offset paper and printing paper, and is required to record graphic and text information in an ink printing or laser printing mode, but only a thermal printer containing a thermal sensitive element is required to record the graphic and text information on the thermal paper.

And has been used in many different fields and situations such as facsimile recording, cash register bills, entertainment bills, medical record papers, measurement record papers, logistics labels, measurement labels, value notes, and the like, because of the convenience of thermal paper. With the expansion of application range and the increase of usage, the demand for thermal paper is increasing. Unlike the earlier method for simply recording simple messages, it is often necessary to first perform a pre-printing operation (such as flexo printing, offset printing, UV printing, etc. which are common printing methods) before using thermal paper, so as to provide more additional information, such as: trademark logo, advertisement information, suggestive information, background pictures and texts, beautifying pictures and texts, and the like, wherein the printing adaptability of the thermal paper is ensured.

However, the thermal paper on the market at present generally has no good printing adaptability, so that poor printing, false image and text and unreal color blocks may occur when the prior printing is performed.

Disclosure of Invention

The application provides thermal paper and a preparation method thereof, which aim to solve the problems that the prior thermal paper has no good printing adaptability, so that the situations of poor printing, virtual pictures and texts and unreal color blocks can occur in the prior printing.

In order to solve the above technical problem, the present application provides a thermal paper, wherein the thermal paper comprises: a paper substrate layer; a base coat disposed on the paper substrate; and the heat-sensitive layer is arranged on the bottom coating and comprises a filler, an adhesive, a color developing agent, a sensitizer, a leuco dye and a lubricant, wherein the filler comprises a high-absorptivity material, the high-absorptivity material is one or a mixture of silica and silicon dioxide, and the silica comprises natural combination of granular silicon dioxide and platy kaolin.

Wherein the mass proportion of the high-absorptivity material in the thermosensitive layer is not less than 20%.

Wherein the mass ratio of the particulate silica in the silica is not less than 50%.

Wherein the primary particle size of the silicon dioxide is 5-30nm, and the secondary particle size is 0.5-5.0 μm.

Wherein the diameter of the micropores of the silicon dioxide is 2-40 nm.

In order to solve the above technical problem, the second technical solution adopted by the present application is: providing thermal paper, wherein the thermal paper comprises a paper base layer, a bottom coating layer, a thermal layer and a top coating layer which are sequentially stacked; the top coating comprises filler, an adhesive, a bridging agent and a lubricant, wherein the mass percentage of the high-absorptivity material in the filler in the top coating is not less than 10%.

In order to solve the above technical problem, the third technical solution adopted by the present application is: provided is a method for preparing thermal paper, wherein the method for preparing the thermal paper comprises the following steps: preparing a thermosensitive layer coating liquid by adopting a filler, an adhesive, a developer dispersion liquid, a sensitizer dispersion liquid, a leuco dye dispersion liquid and a lubricant in a set ratio; wherein, the filler comprises a high-absorptivity material, the high-absorptivity material is one or a mixture of more of silica and silicon dioxide, and the silica comprises particulate silicon dioxide and platy kaolin; and coating the prepared thermosensitive layer coating liquid on a bottom coating layer which is laminated on the paper base layer and drying to obtain the thermosensitive paper.

In order to solve the above technical problem, a fourth technical solution adopted by the present application is: provided is a method for preparing thermal paper, wherein the method for preparing the thermal paper comprises the following steps: preparing a top coating liquid by adopting a filler, an adhesive, a bridging agent and a lubricant in a set ratio; providing a paper base layer, a bottom coating layer and a heat-sensitive layer which are sequentially stacked, coating the prepared top coating layer coating liquid on the heat-sensitive layer and drying to obtain heat-sensitive paper; wherein the mass percentage of the high-absorptivity material in the dried top coating layer coating liquid is not less than 10%.

The beneficial effect of this application is: different from the prior art, the thermosensitive layer in the thermosensitive paper provided by the application comprises a filler, an adhesive, a color developing agent, a sensitizer, a leuco dye and a lubricant, wherein the filler further comprises a high-absorptivity material, the high-absorptivity material is one or more of silica and silica, and the silica comprises particulate silica and platy kaolin, so that the absorptivity and adaptability of the thermosensitive layer to printing ink are effectively improved by adding silica and/or silica with high oil absorption into the thermosensitive layer of the thermosensitive paper, and good printing adaptability can be provided while the basic thermosensitive printing performance of the thermosensitive paper is kept, thereby effectively avoiding the situations of poor printing, virtual image and text and unreal color blocks.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

FIG. 1 is a schematic structural diagram of a first embodiment of thermal paper according to the present application;

FIG. 2 is a schematic structural diagram of a second embodiment of the thermal paper of the present application;

FIG. 3 is a schematic flow chart of a first embodiment of a method for producing thermal paper according to the present application;

fig. 4 is a schematic flow chart of a second embodiment of the method for producing thermal paper according to the present application.

Detailed Description

The present application will be described in further detail with reference to the following drawings and examples. It is to be noted that the following examples are only illustrative of the present application, and do not limit the scope of the present application. Likewise, the following examples are only some examples and not all examples of the present application, and all other examples obtained by a person of ordinary skill in the art without any inventive step are within the scope of the present application.

The terms "first", "second" and "third" in this application are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implying any indication of the number of technical features indicated. Thus, a feature defined as "first," "second," or "third" may explicitly or implicitly include at least one of the feature. In the description of the present application, "plurality" means at least two, e.g., two, three, etc., unless explicitly specifically limited otherwise. All directional indications (such as up, down, left, right, front, and rear … …) in the embodiments of the present application are only used to explain the relative positional relationship between the components, the movement, and the like in a specific posture (as shown in the drawings), and if the specific posture is changed, the directional indication is changed accordingly. Furthermore, the terms "include" and "have," as well as any variations thereof, are intended to cover non-exclusive inclusions. For example, a process, method, system, article, or apparatus that comprises a list of steps or elements is not limited to only those steps or elements listed, but may alternatively include other steps or elements not listed, or inherent to such process, method, article, or apparatus.

Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the application. The appearances of the phrase in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. It is explicitly and implicitly understood by one skilled in the art that the embodiments described herein can be combined with other embodiments.

The present application will be described in detail with reference to the accompanying drawings and examples.

Referring to fig. 1, fig. 1 is a schematic structural diagram of a thermal paper according to a first embodiment of the present application.

In the present embodiment, a thermal paper 1 is provided, and the thermal paper 1 may be applied to entertainment tickets such as cashier tickets, transportation tickets, movie tickets, etc., logistics labels used in express delivery, food labels commonly used in supermarkets, and even printing papers for entertainment tickets, invoices, etc. of securities, so that after a corresponding printing device is used to project preset temperature and illumination of set patterns or characters to the thermal paper 1, the set patterns or characters of corresponding colors are displayed on the thermal paper 1. Of course, in other embodiments, the thermal paper 1 may also be applied in other application scenarios, and the embodiment is not limited thereto.

Specifically, the thermal paper 1 includes: a paper base layer 10, a primer layer 20, and a heat sensitive layer 30.

Wherein, the bottom coat 20 is disposed on the paper substrate 10, the thermosensitive layer 30 is further disposed on the bottom coat 20, and the thermosensitive layer 30 comprises a filler, an adhesive, a developer, a sensitizer, a leuco dye and a lubricant, and the filler further comprises a high-absorptivity material, and the high-absorptivity material is one or a mixture of silica and silica, and the silica further comprises particulate silica and platy kaolin, and it may be a natural combination of particulate silica and platy kaolin, and the chemical composition of silica of the silica in the high-absorptivity material is not less than 80%.

It can be understood that, by adding silica and/or silica with high oil absorption into the heat-sensitive layer 30 of the heat-sensitive paper 1, the absorbability and adaptability of the heat-sensitive layer 30 to printing ink can be effectively improved, so that the basic heat-sensitive printing performance of the heat-sensitive paper 1 can be maintained, and good printing adaptability can be provided.

Optionally, the thermosensitive layer 30 is prepared by mixing 15% to 50% of filler, 15% to 30% of adhesive, 10% to 30% of developer dispersion, 10% to 30% of sensitizer dispersion, 10% to 25% of leuco dye dispersion and 0% to 5% of lubricant, and then coating the mixture on the base coat 20 and drying the mixture.

Optionally, the filler is a blend of one or more of light calcium carbonate, heavy calcium carbonate, washed kaolin with a high absorbency material.

Optionally, the mass fraction of the high-absorbency material in the heat-sensitive layer is not less than 20%.

Optionally, the high-absorptivity material is one or a mixture of silica and silicon dioxide; and the mass proportion of the particulate silicon dioxide in the silica is not less than 50 percent; the primary particle size of the silicon dioxide is 5-30nm, the secondary particle size is 0.5-5.0 μm, and the diameter of the micropore is 2.0-40 nm. Preferably, the silica has a pore diameter of 4.0 to 30 nm.

Optionally, the adhesive is one or more of latex, polyvinyl alcohol and modified starch; the latex is one or a mixture of acrylic latex, styrene-butadiene latex and styrene-acrylic latex; the polyvinyl alcohol is one or a mixture of partial alcoholysis polyvinyl alcohol, complete alcoholysis polyvinyl alcohol, partial alcoholysis modified polyvinyl alcohol and complete alcoholysis modified polyvinyl alcohol; the modified starch is one or more of acidified starch, esterified starch and phosphated starch.

Optionally, the lubricant is one or more of zinc stearate and calcium stearate.

Optionally, the color developing agent dispersion liquid is a mixed liquid of 80-95% of color developing agent and 5-20% of dispersing agent, and the mixed liquid is ground by a grinder to obtain a homogeneous stable dispersion liquid with the particle size of 0.5-1.5 μm and the solid content of 30-50%. The color developing agent is one of 4-hydroxy diphenyl sulfone isopropyl ether, 4- [ [4- (2-allyloxy) phenyl ] sulfonyl ] phenol, dihydroxy diphenyl sulfone, 3' -diallyl-4, 4' -dihydroxy diphenyl sulfone, 4-hydroxy-4 ' -isopropoxy diphenyl sulfone and 4- [ (4- (1-methylethoxy) phenyl) sulfonyl ] phenol.

Optionally, the sensitizer dispersion is a mixed solution of 80-95% of sensitizer and 5-20% of dispersant, and the mixed solution is ground by a grinder to obtain a homogeneous stable dispersion solution with a particle size of 0.8-2.0 μm and a solid content of 30-50%. The sensitizer is one or more of 1, 2-dibenzoyl ethane, benzyl-2-naphthyl ether, dibenzyl oxalate, diphenyl sulfone, diethylene glycol diphenyl ether, 1, 2-dibenzoyl ethane and dimethyl phenoxy ethane.

Optionally, the leuco dye dispersion is a mixed solution of 80-95% of leuco dye and 5-20% of a dispersing agent, and the mixture is ground by a grinder to obtain a homogeneous stable dispersion solution with a particle size of 0.5-1.5 μm and a solid content of 30-50%. The leuco dye is 2-anilino-3-methyl-6-aminofluoran, 3- (N-ethyl-N-isoamyl) amino-6-methyl-7-phenylaminofluoran, 3-N-isoamyl-N-ethylamino-6-methyl-7-phenylaminofluoran, 3- (N-ethyl-N-isoamyl) amino-6-methyl-7-phenylaminofluoran, 3- (N-ethyl-4-toluidino) -6-methyl-7-anilinofluoran, 3-dibutylamino-6-methyl-7-anilinofluoran and 3, 3-bis (4-dimethylaminophenyl) -6-dimethylaminophenylpeptide.

Among them, the silica includes particulate silica and platy kaolin, is a loose structure which cannot be physically separated, and has a unique structure of high specific surface area and high oil absorption. Wherein the silica has a chemical composition of 80% or more of silica, a content of fine particulate silica of 50% or more, and a particle diameter of 0.5 to 5.0. mu.m, preferably 0.5 to 3.0. mu.m. It is understood that the smaller the primary particle size of the silica, the larger the specific surface area, the higher the oil absorption/porosity, and that when the silica pore diameter is 40nm or more, the pores mainly absorb (consume) the adhesive, while when the adhesive in the thermosensitive layer 30 is absorbed into the pores of the silica, the function of self-adhesion in the thermosensitive layer 30 is lost, and when the pore diameter is 40nm or less, the pores mainly tend to absorb the ink.

Therefore, when the silica or silica is used, the ink absorbability can be effectively improved, and the strength of the thermosensitive layer 30 is not reduced by consumption (absorption) of an excessive amount of the adhesive, thereby reducing the printing adaptability of the thermosensitive paper 1.

The silica is a new non-metal mineral product, and is an aggregate mainly comprising quartz (silicon dioxide) and certain clay minerals, and the content of silicon dioxide in the silica is more than 80%, wherein the content of particulate silicon dioxide is more than 50%, and the clay minerals are mainly kaolinite. .

Referring to fig. 2, fig. 2 is a schematic structural diagram of a second embodiment of the thermal paper of the present application. In the present embodiment, the thermal paper 1 includes a paper base layer 10, a base coat layer 20, a thermal layer 30, and a top coat layer 40, which are sequentially stacked.

The top coating 40 specifically comprises a filler, an adhesive, a bridging agent and a lubricant, and the mass percentage of the high-absorptivity material in the filler in the top coating 40 is not less than 10%. In this case, the high-absorbency material in the thermosensitive layer 30 is not particularly required, but may be contained in any amount, for example, the thermosensitive layer 30 may not include the high-absorbency material, or the mass ratio of the high-absorbency material may be any reasonable value such as 10%, 15%, or 20%, and the present application does not limit the content.

Optionally, the top coating 40 is obtained by fully mixing 35% to 50% of filler, 20% to 50% of adhesive, 10% to 30% of bridging agent and 5% to 15% of lubricant into a thermosensitive layer coating liquid with a solid content of 15% to 35%, coating the thermosensitive layer coating liquid on the thermosensitive layer 30 and drying the thermosensitive layer coating liquid.

Optionally, the high-absorptivity material is one or more of silica and silicon dioxide; and the mass proportion of the particulate silicon dioxide in the silica is not less than 50 percent; the primary particle size of the silicon dioxide is 5-30nm, the secondary particle size is 0.5-5.0 μm, and the diameter of the micropore is 2.0-40 nm. Preferably, the silica has a pore diameter of 4.0 to 30 nm; the silica has a particle size of 0.5 to 5.0 μm, preferably 0.5 to 3.0 μm. Optionally, the adhesive is one or more of latex, polyvinyl alcohol and modified starch; the latex is one or a mixture of acrylic latex, styrene-butadiene latex and styrene-acrylic latex; the polyvinyl alcohol is one or a mixture of partial alcoholysis polyvinyl alcohol, complete alcoholysis polyvinyl alcohol, partial alcoholysis modified polyvinyl alcohol and complete alcoholysis modified polyvinyl alcohol; the modified starch is one or more of acidified starch, esterified starch and phosphated starch.

Optionally, the cross-linking agent is one or more of adipic acid dihydrazide, isocyanate, glyoxal, urea-formaldehyde resin and epichlorohydrin.

Optionally, the lubricant is one or more of zinc stearate and calcium stearate.

It can be understood that the thermal paper 1 in the present application can provide good printing adaptability while effectively improving the absorption and adaptability of the thermal layer 30 and/or the top coat layer 40 to printing ink by adding silica and/or silica with high oil absorption degree in the thermal layer 30 and/or the top coat layer 40, so that the basic thermal printing performance of the thermal paper can be maintained.

Based on the general inventive concept, the present application also provides a method for preparing thermal paper, please refer to fig. 3, and fig. 3 is a schematic flow chart of a first embodiment of the method for preparing thermal paper of the present application. The implementation mode comprises the following steps:

s31: the thermosensitive layer coating liquid is prepared by adopting fillers, adhesives, a developer dispersion liquid, a sensitizer dispersion liquid, a leuco dye dispersion liquid and a lubricant in a set ratio, wherein the fillers comprise high-absorptivity materials, the high-absorptivity materials are one or a mixture of silica and silicon dioxide, and the silica comprises micro-particle silicon dioxide and platy kaolin.

Specifically, after providing a paper base layer and a base coat layer which are laminated, a thermosensitive layer coating liquid is first prepared using a filler, an adhesive, a developer dispersion, a sensitizer dispersion, a leuco dye dispersion, and a lubricant in a set ratio.

Wherein, the filler further comprises high-absorptivity material, the high-absorptivity material is one or mixture of silica and silicon dioxide, the silica further comprises particulate silica and platy kaolin, the silica can be natural combination of the particulate silica and the platy kaolin, and the chemical composition of the silica in the high-absorptivity material is not less than 80%.

It can be understood that by adding silica and/or silica with high oil absorption into the material of the thermosensitive layer of the thermosensitive paper, the absorbability and adaptability of the finally prepared thermosensitive layer to printing ink can be effectively improved, so that the basic thermosensitive printing performance of the thermosensitive paper can be kept, and good printing adaptability can be provided.

In a specific embodiment, the thermosensitive layer coating liquid is prepared by adopting 15% -50% of filler, 15% -30% of adhesive, 10% -30% of developer dispersion liquid, 10% -30% of sensitizer dispersion liquid, 10% -25% of leuco dye dispersion liquid and 0% -5% of lubricant, and stirring at high speed to fully mix into a mixed solution with 20-50% of solid content.

Optionally, the high-absorptivity material is one or a mixture of silica and silicon dioxide; and the mass proportion of the particulate silicon dioxide in the silica is not less than 50 percent; the primary particle size of the silicon dioxide is 5-30nm, the secondary particle size is 0.5-5.0 μm, and the diameter of the micropore is 2.0-40 nm. Preferably, the silica has a pore diameter of 4.0 to 30 nm; the silica has a particle size of 0.5 to 5.0 μm, preferably 0.5 to 3.0 μm.

Optionally, the adhesive is one or more of latex, polyvinyl alcohol and modified starch; the latex is one or a mixture of acrylic latex, styrene-butadiene latex and phenyl propyl latex; the polyvinyl alcohol is one or a mixture of partial alcoholysis polyvinyl alcohol, complete alcoholysis polyvinyl alcohol, partial alcoholysis modified polyvinyl alcohol and complete alcoholysis modified depolymerization polyvinyl alcohol; the modified starch is one or more of acidified starch, esterified starch and phosphated starch.

Optionally, the lubricant is one or more of zinc stearate and calcium stearate.

In another embodiment, when only a paper substrate is provided, it is also necessary to prepare a primer coating liquid, for example, using 75-90% of filler and 25-10% of adhesive, to fully mix the primer coating liquid with 20-50% of solid content after stirring at high speed for 30-60 minutes.

Optionally, the filler is a mixture of one or more of calcined kaolin, ground calcium carbonate, light calcium carbonate, silica, and a plastic pigment.

Optionally, the adhesive is one or more of latex, polyvinyl alcohol and starch; the latex is one or a mixture of acrylic latex, styrene-butadiene latex and styrene-acrylic latex.

Optionally, the polyvinyl alcohol is one or more of partially alcoholized polyvinyl alcohol with a degree of polymerization of 1000-2000-type and fully alcoholized polyvinyl alcohol, and the starch is one or more of acidified starch, esterified starch and native starch.

S32: and coating the prepared thermosensitive layer coating liquid on a bottom coating layer which is laminated on the paper base layer and drying to obtain the thermosensitive paper.

Further, the prepared heat-sensitive layer coating liquid is applied to an undercoat layer laminated on a paper base layer, and the prepared heat-sensitive layer coating liquid is applied to the undercoat layer by one of any reasonable process methods such as film transfer, roll coating, blade coating, air knife coating, curtain coating, and the like using a coater, and dried, to obtain a final heat-sensitive paper.

In another embodiment, the prepared heat-sensitive layer coating liquid is coated on a bottom coating layer which is laminated on a paper base layer, and the corresponding coating weight is ensured to be 3.0-6.0 per square meter, so as to dry, thereby obtaining the final finished heat-sensitive paper.

In another embodiment, when only the paper base layer is provided, the prepared undercoat layer coating liquid is first coated on the paper base layer and dried, and the prepared thermosensitive layer coating liquid is further coated on the dried undercoat layer coating liquid and dried to obtain the final finished thermosensitive paper.

Referring to fig. 4, fig. 4 is a schematic flow chart of a second embodiment of a method for preparing thermal paper according to the present application. The implementation mode comprises the following steps:

s41: and preparing the top coating liquid by adopting the filler, the adhesive, the bridging agent and the lubricant in a set ratio.

Specifically, a top coating liquid is prepared by adopting a filler, an adhesive, a bridging agent and a lubricant in a set ratio.

In a specific embodiment, the top coating liquid is obtained by fully mixing 35% -50% of filler, 20% -50% of adhesive, 10% -30% of bridging agent and 5% -15% of lubricant into a mixed solution with a solid content of 15-35%.

Optionally, the high-absorptivity material is one or more of silica and silicon dioxide; and the mass proportion of the particulate silicon dioxide in the silica is not less than 50 percent; the primary particle size of the silicon dioxide is 5-30nm, the secondary particle size is 0.5-5.0 μm, and the diameter of the micropore is 2.0-40 nm. Preferably, the silica has a pore diameter of 4.0 to 30 nm; the silica has a particle size of 0.5 to 5.0 μm, preferably 0.5 to 3.0 μm.

Optionally, the lubricant is one or more of zinc stearate and calcium stearate.

S42: providing a paper base layer, a bottom coating layer and a heat-sensitive layer which are sequentially stacked, coating the prepared top coating liquid on the heat-sensitive layer and drying to obtain heat-sensitive paper; wherein the mass percentage of the high-absorptivity material in the dried top coating layer coating liquid is not less than 10%.

Further, a paper base layer, an undercoat layer and a heat-sensitive layer are provided in order to coat the prepared top coat coating liquid on the heat-sensitive layer, for example, the prepared top coat coating liquid is coated on the heat-sensitive layer by one of any reasonable process methods such as film transfer, roll coating, blade coating, air knife coating, curtain coating and the like using a coater, and dried to obtain the final heat-sensitive paper.

Wherein, the filler in the top coat coating liquid also comprises a high-absorptivity material, and the mass percentage of the high-absorptivity material in the dried top coat coating liquid is not less than 10%.

In another embodiment, the prepared top coating liquid is uniformly coated on the dried thermosensitive layer coating liquid, and the corresponding coating weight is ensured to be 2.0-4.0 per square meter, so as to dry, thereby obtaining the final finished thermosensitive paper.

In another embodiment, when the paper base layer and the bottom coating layer are stacked, it is further necessary to first prepare the heat-sensitive layer coating liquid using the filler, the adhesive, the color developer dispersion liquid, the sensitizer dispersion liquid, the leuco dye dispersion liquid, and the lubricant in a predetermined ratio, to coat the prepared heat-sensitive layer coating liquid on the bottom coating layer stacked on the paper base layer and dry it, and further coat the prepared top coating layer coating liquid on the dried heat-sensitive layer coating liquid and dry it.

In one embodiment, 88% dihydroxydiphenyl sulfone and 12% polyvinyl alcohol are mixed and dispersed to form a dispersion with a solid content of 48%, and the mixture is ground in a grinder to a particle size of 1.0 μm to obtain a developer dispersion; mixing and dispersing 85% of diethylene glycol diphenyl ether and 15% of polyvinyl alcohol into a dispersion liquid with a solid content of 45%, and grinding the dispersion liquid in a grinder until the particle size is 1.0 mu m to obtain a sensitizer dispersion liquid; mixing and dispersing 90% of 2-anilino-3-methyl-6-aminofluorane and 10% of polyvinyl alcohol into a dispersion liquid with a solid content of 50%, and grinding the dispersion liquid in a grinder until the particle size is 1.0 mu m to obtain a leuco dye dispersion liquid; further, 20% of the developer dispersion, 20% of the sensitizer dispersion, 12% of the leuco dye dispersion, 8% of water-washed kaolin, 20% of silica, 18% of polyvinyl alcohol having a high degree of polymerization and completely alcoholyzed, and 2% of zinc stearate were mixed and dispersed to obtain a heat-sensitive layer coating solution having a solid content of 32%.

Further, 35% of washing kaolin, 13% of silicon dioxide, 29% of completely alcoholysis modified polyvinyl alcohol, 15% of glyoxal and 8% of zinc stearate are mixed and dispersed to form a top coating liquid with a solid content of 28%.

Further, uniformly coating the prepared thermosensitive layer coating liquid on a bottom coating layer laminated on the paper base layer by using a coating machine, and drying after ensuring that the corresponding coating amount is 4.8 g/square meter; and further uniformly coating the prepared top coating liquid on the thermosensitive layer coated and dried on the bottom coating by using a coating machine, and drying after ensuring that the corresponding coating amount is 3.0 g/square meter to obtain the final finished thermosensitive paper.

In another example, 85% of 3,3 '-diallyl-4, 4' -dihydroxydiphenyl sulfone and 15% of polyvinyl alcohol were mixed and dispersed to obtain a dispersion having a solid content of 38%, and the mixture was ground in a grinder to a particle size of 1.2 μm to obtain a developer dispersion; mixing and dispersing 85% of dimethyl phenoxy ethane and 15% of polyvinyl alcohol into dispersion liquid with solid content of 44%, and grinding the dispersion liquid in a grinder until the particle size is 1.6 mu m to obtain a sensitizer dispersion liquid; mixing and dispersing 3-N-isoamyl-N-ethylamino-6-methyl-7-phenylaminofluorane 90% and polyvinyl alcohol 10% into dispersion liquid with solid content of 48%, and grinding the dispersion liquid in a grinder until the particle size is 1.0 mu m to obtain leuco dye dispersion liquid; further, 20% of the developer dispersion, 21% of the sensitizer dispersion, 12% of the leuco dye dispersion, 8% of water-washed kaolin, 5% of silica, 14% of silica, 18% of polyvinyl alcohol having a high polymerization degree and being completely alcoholyzed, and 2% of zinc stearate were mixed and dispersed to prepare a heat-sensitive layer coating liquid having a solid content of 38%.

Further, 38% of washing kaolin, 12% of silicon dioxide, 32% of completely alcoholysis modified polyvinyl alcohol, 13% of glyoxal and 8% of zinc stearate are mixed and dispersed to form a top coating liquid with the solid content of 26%.

Further, uniformly coating the prepared thermosensitive layer coating liquid on a bottom coating layer laminated on the paper base layer by using a coating machine, and drying after ensuring that the corresponding coating amount is 4.0 g/square meter; and further uniformly coating the prepared top coating liquid on the thermosensitive layer coated and dried on the bottom coating by using a coating machine, and drying after ensuring that the corresponding coating amount is 3.2 g/square meter to obtain the final finished thermosensitive paper.

In another example, a dispersion having a solid content of 50% was prepared by mixing 4-hydroxydiphenylsulfone isopropyl ether 90% and polyvinyl alcohol 10%, and the mixture was ground in a mill to a particle size of 1.2 μm to obtain a developer dispersion; 88 percent of diphenyl sulfone and 12 percent of polyvinyl alcohol are mixed and dispersed into dispersion liquid with solid content of 45 percent, and the dispersion liquid is ground in a grinder to the particle size of 0.8 mu m to obtain a sensitizer dispersion liquid; mixing and dispersing 88% of 3- (N-ethyl-4-toluidino) -6-methyl-7-anilinofluorane and 12% of polyvinyl alcohol into a dispersion liquid with solid content of 48%, and grinding the dispersion liquid in a grinder until the particle size is 0.9 mu m to obtain a leuco dye dispersion liquid; further, 21% of the developer dispersion, 22% of the sensitizer dispersion, 14% of the leuco dye dispersion, 12% of water-washed kaolin, 15% of light calcium carbonate, 12% of styrene-butadiene latex, and 5% of esterified starch were mixed and dispersed to obtain a heat-sensitive layer coating liquid having a solid content of 32%.

Further, 35% of washing kaolin, 5% of silica, 11% of silicon dioxide, 29% of completely alcoholysis modified polyvinyl alcohol, 11% of epichlorohydrin and 9% of calcium stearate are mixed and dispersed to form the top coating liquid with the solid content of 26%.

Further, uniformly coating the prepared thermosensitive layer coating liquid on a bottom coating layer laminated on the paper base layer by using a coating machine, and drying after ensuring that the corresponding coating amount is 4.2 g/square meter; and further uniformly coating the prepared top coating liquid on the thermosensitive layer coated and dried on the bottom coating by using a coating machine, and drying after ensuring that the corresponding coating amount is 3.5 g/square meter to obtain the final finished thermosensitive paper.

In another example, 85% of 4-hydroxy-4' -isopropoxydiphenyl sulfone and 15% of polyvinyl alcohol were mixed and dispersed to a dispersion having a solid content of 50%, and ground in a grinder to a particle size of 0.9 μm to obtain a developer dispersion; 88 percent of diphenyl sulfone and 12 percent of polyvinyl alcohol are mixed and dispersed into dispersion liquid with the solid content of 42 percent, and the dispersion liquid is ground in a grinder to the particle size of 1.8 mu m to obtain a sensitizer dispersion liquid; mixing and dispersing 3- (N-ethyl-4-toluidino) -6-methyl-7-anilinofluorane 90% and polyvinyl alcohol 10% into a dispersion liquid with the solid content of 47%, and grinding the dispersion liquid in a grinder until the particle size is 0.8 mu m to obtain a leuco dye dispersion liquid; further, 21% of the developer dispersion, 19% of the sensitizer dispersion, 11% of the leuco dye dispersion, 5% of light calcium carbonate, 13% of silica, 10% of silica, 17% of polyvinyl alcohol having a high polymerization degree and being completely alcoholyzed, and 4% of zinc stearate were mixed and dispersed to obtain a heat-sensitive layer coating liquid having a solid content of 30%.

And then, uniformly coating the prepared thermosensitive layer coating liquid on a bottom coating layer which is laminated on the paper base layer by using a coating machine, and drying after ensuring that the corresponding coating amount is 5.0 g/square meter to obtain the final finished thermosensitive paper.

In another example, a dispersion having a solid content of 50% was prepared by mixing 4-hydroxydiphenylsulfone isopropyl ether 90% and polyvinyl alcohol 10%, and the mixture was ground in a mill to a particle size of 1.2 μm to obtain a developer dispersion; mixing and dispersing 88% of diethylene glycol diphenyl ether and 12% of polyvinyl alcohol into a dispersion liquid with a solid content of 45%, and grinding the dispersion liquid in a grinder until the particle size is 0.8 mu m to obtain a sensitizer dispersion liquid; mixing and dispersing 88% of 2-anilino-3-methyl-6-aminofluorane and 12% of polyvinyl alcohol into a dispersion liquid with the solid content of 48%, and grinding the dispersion liquid in a grinder until the particle size is 0.9 mu m to obtain a leuco dye dispersion liquid; further, 20% of the developer dispersion, 22% of the sensitizer dispersion, 12% of the leuco dye dispersion, 10% of water-washed kaolin, 4% of light calcium carbonate, 13% of silica, 10% of styrene-butadiene latex, 7% of esterified starch and 3% of zinc stearate were mixed and dispersed to obtain a heat-sensitive layer coating liquid having a solid content of 32%.

Further, 39% of washing kaolin, 8% of silica, 7% of silicon dioxide, 28% of completely alcoholysis modified polyvinyl alcohol, 10% of epoxy chloropropane and 8% of calcium stearate are mixed and dispersed to form the top coating liquid with the solid content of 25%.

Further, uniformly coating the prepared thermosensitive layer coating liquid on a bottom coating layer laminated on the paper base layer by using a coating machine, and drying after ensuring that the corresponding coating amount is 4.2 g/square meter; and further uniformly coating the prepared top coating liquid on the thermosensitive layer coated and dried on the bottom coating by using a coating machine, and drying after ensuring that the corresponding coating amount is 3.3 g/square meter to obtain the final finished thermosensitive paper.

The beneficial effect of this application is: different from the prior art, the thermosensitive layer in the thermosensitive paper provided by the application comprises a filler, an adhesive, a color developing agent, a sensitizer, a leuco dye and a lubricant, wherein the filler further comprises a high-absorptivity material, the high-absorptivity material is one or a mixture of silica and silicon dioxide, and the silica comprises particulate silica and platy kaolin. By adding silica and/or silicon dioxide with high oil absorption into the heat-sensitive layer of the heat-sensitive paper, the absorbability and the adaptability of the heat-sensitive layer to printing ink are effectively improved, so that the basic heat-sensitive printing performance of the heat-sensitive paper is kept, good printing adaptability can be provided, and the situations of poor printing, virtual image-text and unreal color blocks can be effectively avoided.

The above description is only a part of the embodiments of the present application, and not intended to limit the scope of the present application, and all equivalent devices or equivalent processes performed by the content of the present application and the attached drawings, or directly or indirectly applied to other related technical fields, are also included in the scope of the present application.

Claims

1. A thermal paper, characterized in that the thermal paper comprises:

a paper substrate layer;

a base coat disposed on the paper substrate;

the heat-sensitive layer is arranged on the bottom coating and comprises filler, an adhesive, a color developing agent, a sensitizer, a leuco dye and a lubricant, wherein the filler comprises a high-absorptivity material, the high-absorptivity material is one or a mixture of silica and silicon dioxide, and the silica comprises particulate silica and platy kaolin.

2. The thermal paper according to claim 1,

the mass proportion of the high-absorptivity material in the thermosensitive layer is not less than 20%.

3. The thermal paper according to claim 1,

the mass proportion of the particulate silica in the silica is not less than 50%.

4. The thermal paper according to claim 1,

the primary particle size of the silicon dioxide is 5-30nm, and the secondary particle size is 0.5-5.0 μm.

5. The thermal paper according to claim 4,

the diameter of the micropores of the silicon dioxide is 2-40 nm.

6. The thermal paper is characterized by comprising a paper base layer, a bottom coating layer, a thermal layer and a top coating layer which are sequentially stacked;

wherein the top coat comprises the filler, the adhesive, a bridging agent and the lubricant, wherein the mass proportion of the high-absorptivity material in the filler in the top coat is not less than 10%.

7. The preparation method of the thermal paper is characterized by comprising the following steps:

preparing a thermosensitive layer coating liquid by adopting a filler, an adhesive, a developer dispersion liquid, a sensitizer dispersion liquid, a leuco dye dispersion liquid and a lubricant in a set ratio; wherein, the filler comprises a high-absorptivity material, the high-absorptivity material is one or a mixture of silica and silicon dioxide, and the silica comprises particulate silicon dioxide and platy kaolin;

and coating the prepared thermosensitive layer coating liquid on a bottom coating layer which is laminated on a paper base layer and drying to obtain the thermosensitive paper.

8. The method of producing thermal paper according to claim 7,

9. The method of producing thermal paper according to claim 7,

10. The preparation method of the thermal paper is characterized by comprising the following steps:

preparing a top coating liquid by adopting the filler, the adhesive, the bridging agent and the lubricant in a set ratio;

providing a paper base layer, a bottom coating layer and a heat-sensitive layer which are sequentially stacked, coating the prepared top coating liquid on the heat-sensitive layer and drying to obtain heat-sensitive paper; wherein the mass ratio of the high-absorptivity material in the dried top coating layer coating liquid is not less than 10%.