阅读说明：本技术 一种隔热热敏纸预涂层及其制备方法 (Heat-insulating thermal paper precoating and preparation method thereof ) 是由 汪丹越 张恒頔 于 2020-12-23 设计创作，主要内容包括：本发明公开了一种隔热热敏纸预涂层及其制备方法。所述隔热热敏纸预涂层的原料包括以重量份数计的60-80份填料、5-25份已膨胀微球、8-13份胶黏剂、0.2-1份分散剂、3-10份润滑剂及0.2-0.5份消泡剂。制备方法为将填料、已膨胀微球、胶黏剂、分散剂与水混合均匀,配制成浆料,然后加入润滑剂和消泡剂；用涂布机将浆料涂布于热敏原纸上,干燥压光,即得隔热热敏纸预涂层。本发明采用已膨胀微球作为隔热填料,少量添加即可达到好的隔热效果,提高纸基层的保温隔热性,增加显色的灵敏性和显色的饱和性；引入小粒径的已膨胀微球,涂层表面更加平滑,能够改善图文的鲜明度和显色的灵敏度。(The invention discloses a precoating layer of heat-insulating heat-sensitive paper and a preparation method thereof. The raw materials of the precoating layer of the heat-insulating heat-sensitive paper comprise, by weight, 60-80 parts of filler, 5-25 parts of expanded microspheres, 8-13 parts of adhesive, 0.2-1 part of dispersant, 3-10 parts of lubricant and 0.2-0.5 part of defoamer. The preparation method comprises the steps of uniformly mixing the filler, the expanded microspheres, the adhesive, the dispersing agent and water to prepare slurry, and then adding the lubricating agent and the defoaming agent; and coating the sizing agent on the thermal sensitive base paper by using a coating machine, and drying and press polishing to obtain the thermal insulation thermal sensitive paper precoating. The expanded microspheres are used as heat insulation filler, and a good heat insulation effect can be achieved by adding a small amount of the expanded microspheres, so that the heat insulation property of the paper base layer is improved, and the developing sensitivity and the developing saturation are improved; the expanded microspheres with small particle size are introduced, so that the surface of the coating is smoother, and the brightness of the image and text and the sensitivity of color development can be improved.)

1. The precoating layer is characterized in that raw materials comprise, by weight, 60-80 parts of filler, 5-25 parts of expanded microspheres, 8-13 parts of adhesive, 0.2-1 part of dispersant, 3-10 parts of lubricant and 0.2-0.5 part of defoamer.

2. The pre-coating of insulated thermal paper according to claim 1, wherein the filler is any one or more of calcium carbonate, silica, kaolin, calcined kaolin, aluminum hydroxide, and titanium dioxide.

3. The precoat of insulating thermal paper according to claim 1, wherein the adhesive is any one or more of styrene-butadiene latex, styrene-acrylic latex, polyvinyl alcohol, acrylic latex, and starch.

4. The pre-coat of insulated thermal paper according to claim 1, wherein the expanded microspheres are in a core-shell structure, wherein the shell material is a thermoplastic polymer and the core material is a blowing agent having a boiling point not higher than the boiling point of the shell material; the particle size of the expanded microspheres is 15-30 μm.

5. The precoat of thermally insulating thermal paper of claim 1, wherein the dispersant is any one or more of sodium polyacrylate, sodium hexametaphosphate, and polycarboxylate.

6. The precoat of insulating thermal paper according to claim 1, wherein the lubricant is any one or more of paraffin wax, zinc stearate, calcium stearate, polyethylene wax, and stearic acid amide.

7. The pre-coat of thermally insulating thermal paper as claimed in claim 1, wherein the defoamer is a silicone defoamer.

8. The method for preparing the precoat of the heat-insulating and heat-sensitive paper as claimed in any one of claims 1 to 7, characterized in that the filler, the expanded microspheres, the adhesive, the dispersant and water are uniformly mixed, stirred for 20 to 40min to prepare slurry with the solid mass content of 35 to 55 percent, and then the lubricant and the defoamer are added and continuously stirred for 10 to 20 min; and coating the sizing agent on the thermal sensitive base paper by using a coating machine, and drying and press polishing to obtain the thermal insulation thermal sensitive paper precoating.

9. The method for preparing the precoat of the heat-insulating and heat-sensitive paper of claim 8, wherein the coating weight of the coating machine is 6 to 9g/m²。

Technical Field

The invention relates to a precoating layer of heat-insulating thermal paper and a preparation method thereof, belonging to the technical field of thermal paper.

Background

The thermosensitive recording paper is used as information recording material, and has color forming material coating on the surface of the paper, and the heat signal excites the self-developing thermosensitive recording paper. The printing device has the characteristics of small size, flexibility, single and cheap printing consumables, simple and convenient printing operation, quiet and quick printing process and fine and clear printed products, and is widely applied to the fields of fax communication, medical imaging, financial bills, logistics labels and the like.

The thermal paper is through thermal printer's the printer head heat transfer when using, and the paper base heat-proof quality of most thermal paper is relatively poor, and the heat very easily migrates to paper basic unit or need not the imaging area, causes thermal loss, and the sensitivity of greatly reduced colour development, the image of printing out is not clear enough, needs higher heat to increase the saturation of colour development, causes the very big waste of resource. Patent CN209479150U adopts microcapsules coated with nano silica as precoating layer, and the heat insulation property is not sufficient.

Disclosure of Invention

The technical problem to be solved by the invention is as follows: how to reduce the migration of the heat-sensitive layer coating to the paper base layer, improve the heat preservation and heat insulation performance of the paper base layer, and increase the color development sensitivity and the color development saturation.

In order to solve the technical problem, the invention provides a precoating layer of heat-insulating heat-sensitive paper, which is characterized in that raw materials comprise, by weight, 60-80 parts of filler, 5-25 parts of expanded microspheres, 8-13 parts of adhesive, 0.2-1 part of dispersant, 3-10 parts of lubricant and 0.2-0.5 part of defoaming agent.

Preferably, the filler is any one or more of calcium carbonate, silica, kaolin, calcined kaolin, aluminum hydroxide and titanium dioxide.

Preferably, the adhesive is any one or more of styrene-butadiene latex, styrene-acrylic latex, polyvinyl alcohol, acrylic latex and starch.

Preferably, the expanded microspheres are in a core-shell structure, wherein the shell material is a thermoplastic polymer, and the core material is a foaming agent with a boiling point not higher than that of the shell material; the particle size of the expanded microspheres is 15-30 μm.

Preferably, the dispersant is any one or more of sodium polyacrylate, sodium hexametaphosphate and polycarboxylate.

Preferably, the lubricant is any one or more of paraffin, zinc stearate, calcium stearate, polyethylene wax and stearic acid amide.

Preferably, the defoamer is a silicone defoamer.

The invention also provides a preparation method of the precoat of the heat-insulating heat-sensitive paper, which is characterized in that the filler, the expanded microspheres, the adhesive, the dispersant and water are uniformly mixed and stirred for 20-40min to prepare slurry with the solid mass content of 35-55%, and then the lubricant and the defoamer are added and continuously stirred for 10-20 min; and coating the sizing agent on the thermal sensitive base paper by using a coating machine, and drying and press polishing to obtain the thermal insulation thermal sensitive paper precoating.

Preferably, the coating amount of the coating machine is 6-9g/m²。

The expanded microspheres are used as heat insulation filler, and a good heat insulation effect can be achieved by adding a small amount of the expanded microspheres, so that the heat insulation property of the paper base layer is improved, and the developing sensitivity and the developing saturation are improved; the expanded microspheres with small particle size are introduced, so that the surface of the coating is smoother, and the brightness of the image and text and the sensitivity of color development can be improved.

Detailed Description

In order to make the invention more comprehensible, preferred embodiments are described in detail below.

The expanded microspheres used in each example were those produced by kurari technologies (shanghai) ltd.

Example 1

1. 60 parts of calcium carbonate, 25 parts of expanded microspheres, 8 parts of styrene-butadiene latex, 5 parts of polyvinyl alcohol, 1 part of sodium hexametaphosphate and water are uniformly mixed and stirred at a high speed for 20min to prepare slurry with the solid content of 55 wt%.

2. 10 parts of paraffin and 0.2 part of organic silicon defoamer are added and stirred for 10 min.

3. Coating the precoating slurry by a coaterSpreading on heat-sensitive base paper, drying and press polishing to form heat-sensitive precoating layer with coating weight of 6g/m²。

Comparative example 1

1. 85 parts of calcium carbonate, 8 parts of styrene-butadiene latex, 5 parts of polyvinyl alcohol, 1 part of sodium hexametaphosphate and water are uniformly mixed and stirred at a high speed for 20min to prepare slurry with the solid content of 55 wt%.

2. 10 parts of paraffin and 0.2 part of organic silicon defoamer are added and stirred for 10 min.

3. Coating the precoating slurry on heat-sensitive base paper by a coating machine, drying and calendaring to form a heat-sensitive precoating layer, wherein the coating weight is 6g/m²。

Example 2

1. Uniformly mixing 80 parts of calcined kaolin, 5 parts of expanded microspheres, 8 parts of styrene-acrylic latex, 2 parts of polyvinyl alcohol, 0.2 part of sodium polyacrylate and water, and stirring at a high speed for 40min to prepare slurry with the solid content of 35 wt%.

2. 3 parts of zinc stearate and 0.5 part of organic silicon defoamer are added and stirred for 20 min.

3. Coating the precoating slurry on heat-sensitive base paper by a coating machine, drying and calendaring to form a heat-sensitive precoating layer, wherein the coating weight is 9g/m²。

Comparative example 2

1. 85 parts of calcined kaolin, 8 parts of styrene-acrylic latex, 2 parts of polyvinyl alcohol, 0.2 part of sodium polyacrylate and water are uniformly mixed and stirred at a high speed for 40min to prepare slurry with the solid content of 35%.

2. 3 parts of zinc stearate and 0.5 part of organic silicon defoamer are added and stirred for 20 min.

3. Coating the precoating slurry on heat-sensitive base paper by a coating machine, drying and calendaring to form a heat-sensitive precoating layer, wherein the coating weight is 9g/m²。

Example 3

1. 67 parts of calcium carbonate, 15 parts of expanded microspheres, 8 parts of styrene-acrylic latex, 0.5 part of sodium hexametaphosphate and water are uniformly mixed and stirred at a high speed for 30min to prepare slurry with the solid content of 45%.

2. 6 parts of zinc stearate and 0.3 part of organic silicon defoamer are added and stirred for 20 min.

3. Coating the precoating slurry on a coaterDrying and calendaring the heat-sensitive base paper to form a heat-sensitive precoating layer with the coating weight of 7g/m²。

Comparative example 3

1. 82 parts of calcium carbonate, 8 parts of styrene-acrylic latex, 0.5 part of sodium hexametaphosphate and water are uniformly mixed and stirred at a high speed for 30min to prepare slurry with the solid content of 45%.

2. 6 parts of zinc stearate and 0.3 part of organic silicon defoamer are added and stirred for 20 min.

3. Coating the precoating slurry on heat-sensitive base paper by a coating machine, drying and calendaring to form a heat-sensitive precoating layer, wherein the coating weight is 7g/m²。

The thermal conductivity of examples 1 to 3 and comparative examples 1 to 3 are shown in Table 1.

TABLE 1