A paper primer and a method for preparing the same

Abstract

The application relates to the field of paper primer sizing, in particular to a paper primer sizing and a preparation method thereof, and the paper primer sizing is prepared from the following raw materials in parts by weight: polyvinyl acetate emulsion 40-60 parts, styrene-acrylate emulsion 10-20 parts, leveling agent 1-5 parts, tackifier 2-4 parts, wetting agent 5-10 parts, water 10-20 parts, emulsifier 2-4 parts and curing agent 1-2 parts. The paper primer sizing prepared from the above raw materials has good fluidity, can be uniformly coated on the surface of common paper, forms a smooth and flat primer layer, has good high-temperature resistance, is beneficial to subsequent aluminum plating operation, reduces the phenomenon of color explosion and ashing of aluminum-plated composite paper caused by uneven primer layer, and is not selective to the base paper and can be used for general paper, has wide applicability, does not need to use special aluminum-plated base paper, and can effectively save enterprise cost.

Description

TECHNICAL FIELD

[0001] The application relates to the field of paper primer coating, in particular to a paper primer coating and a preparation method thereof. BACKGROUND

[0002] Aluminum-coated film composite paper is one of commonly used packaging materials. The finished product contains plastic, which can improve the aluminum spraying firmness of the aluminum-coated film composite paper, so that the aluminum-coated film composite paper is not prone to color explosion phenomenon and has good mechanical processing performance. However, plastic is not degradable and is not environmentally friendly. Therefore, people begin to look for alternative ways. For example, direct aluminum-coated composite paper does not contain plastic and has high environmental protection, and is one of the preferred choices for environmentally friendly packaging.

[0003] The direct aluminum-coated composite paper mainly comprises a base paper layer, a bottom paper layer, a primer layer, an aluminum-coated layer and a top coating layer, and is mainly prepared by direct aluminum coating and transfer aluminum coating. The transfer aluminum coating can use ordinary paper as the bottom paper and can be mass-produced. The reason is that: the transfer aluminum coating is prepared by coating the primer layer on the surface of the transfer film, then pressing the primer layer to the bottom paper, tearing off the transfer film, and peeling off the primer layer on the surface of the transfer film. The surface flatness of the primer layer is high, and then the aluminum is coated on the surface of the bottom paper-primer layer to obtain the aluminum-coated paper (bottom paper-primer layer-aluminum-coated layer); the composite adhesive is applied on the surface of the base paper layer, and then the bottom paper of the aluminum-coated paper is laminated; and finally, the top coating layer is coated on the surface of the aluminum-coated layer of the aluminum-coated paper. However, the above preparation method is relatively complex in actual operation and has high labor cost.

[0004] The direct aluminum coating is prepared by coating the primer adhesive on the surface of the bottom paper to form the primer layer, and then vacuum-coating the aluminum film on the surface of the primer layer and coating the top coating layer on the aluminum-coated layer. The operation is simple, fast and easy to produce. However, the bottom paper for direct aluminum coating requires high quality, and currently special paper is basically used. The reason is that the special bottom paper for direct aluminum-coated composite paper is generally subjected to super pressure treatment and has high flatness. The surface fiber structure of the paper not subjected to super pressure treatment is rough and loose, so that the general primer coating is not easy to form a film on the surface of the bottom paper or the film is not flat, so that the aluminum-coated surface is dark in color or color explosion phenomenon occurs. SUMMARY

[0005] In order to solve the problem of poor flatness of the primer layer caused by coating the primer adhesive on the general bottom paper, the application provides a paper primer coating and a preparation method thereof.

[0006] In a first aspect, the application provides a paper primer coating, which adopts the following technical scheme:

[0007] A paper primer coating is prepared from the following raw materials by weight:

[0008] Polyvinyl acetate emulsion 40-60 parts

[0009] Styrene-acrylate emulsion 10-20 parts

[0010] leveling agent 1-5 parts

[0011] tackifier 2-4 parts

[0012] wetting agent 5-10 parts

[0013] water 10-20 parts

[0014] emulsifier 2-4 parts

[0015] curing agent 1-2 parts.

[0016] By adopting the technical scheme, the paper bottom glue can be directly coated on the surface of the paper, and the bottom glue layer after curing has high performance flatness and good smoothness, which is beneficial to the subsequent aluminum plating operation, and the aluminum plating layer has good gloss. By adopting the paper bottom glue of the application, it can be applied to general paper to form a smooth and flat bottom glue layer on the surface of the general paper, without the need to specially select expensive base paper, and the problem of high production cost can be effectively solved. By adopting polyvinyl acetate emulsion, styrene-acrylate emulsion, leveling agent, tackifier, wetting agent, water, emulsifier and curing agent, good fluidity and bonding performance are obtained, and the paper bottom glue can be uniformly coated on the surface of the base paper, so that the paper bottom glue forms a smooth and flat bottom glue layer after curing.

[0017] The surface of general paper is rough and has small gaps. The polyvinyl acetate emulsion and the styrene-acrylate emulsion are used together, which can fully fill the surface of general paper, so that the surface of the base paper is flat, and then a flat and smooth bottom coating layer is formed on the surface.

[0018] The polyvinyl acetate emulsion has good adhesion and can be used to prepare paper bottom glue to improve the bonding performance of the paper bottom glue. However, it has poor creep resistance and heat resistance, and the aluminum plating temperature of the aluminum plated composite paper is generally between 200-400℃, which is not conducive to aluminum plating. Therefore, the styrene-acrylate emulsion is added in the application to improve the heat resistance of the paper bottom glue, so that the bottom glue layer formed by the paper bottom glue will not be raised or burst during the aluminum plating process.

[0019] Preferably, the styrene-acrylate emulsion is a modified styrene-acrylate emulsion, which is prepared by the following preparation method:

[0020] 1) Polyvinyl alcohol and water are added to the reaction kettle and stirred for 20-40 min; then styrene-acrylate emulsion is added, and after stirring for 0.5-1 h, a milky white pre-emulsion is obtained;

[0021] 2) mixing the silicone-modified acrylate emulsion, silane coupling agent, Tween and nano-silica, high-speed stirring, adding the milky white pre-emulsion, stirring until the viscosity is 3000-8000 mPa·s, to obtain the modified styrene-acrylate emulsion.

[0022] By adopting the above technical scheme, the modified styrene-acrylate emulsion prepared has good compatibility with the polyvinyl acetate emulsion, further improves the uniformity of the paper primer glue, and reduces the problem of uneven and rough primer glue layer caused by uneven mixing of the styrene-acrylate emulsion and the polyvinyl acetate emulsion. At the same time, the silicone-modified acrylate emulsion is added in the modification process, so that the modified styrene-acrylate emulsion is used with the polyvinyl acetate emulsion, leveling agent, tackifier, wetting agent, water, emulsifier and curing agent, which can further improve the flatness and smoothness of the primer layer formed by the paper primer glue.

[0023] Preferably, the weight parts of the raw materials used to prepare the modified acrylate-acrylate emulsion are as follows:

[0024] Styrene-acrylate emulsion 20-30 parts

[0025] Polyvinyl alcohol 5-10 parts

[0026] Silicone-modified acrylate emulsion 10-20 parts

[0027] Silane coupling agent 1-3 parts

[0028] Tween 2-4 parts

[0029] Water 20-40 parts

[0030] Nano-silica 2-5 parts.

[0031] By adopting the above technical scheme, the amount of the modified acrylate-acrylate emulsion is optimized, the compatibility of the modified styrene-acrylate emulsion with the polyvinyl acetate emulsion is improved, and at the same time, the flatness and smoothness of the paper primer glue prepared using the modified styrene-acrylate emulsion can be further improved after curing.

[0032] Preferably, the solid content of the silicone-modified acrylate emulsion is 40-50%, and the number average molecular weight of the silicone-modified acrylate is 40-150 thousand.

[0033] By adopting the above technical scheme, the parameters of the silicone-modified acrylate emulsion are optimized, which can improve the compatibility of the modified styrene-acrylate emulsion with the polyvinyl acetate emulsion, and also improve the flatness and smoothness of the paper primer glue after curing.

[0034] Preferably, the weight ratio of the polyvinyl acetate emulsion to the styrene-acrylate emulsion is (50-55):10.

[0035] By adopting the above technical solution, the polyvinyl acetate emulsion and the styrene-acrylate emulsion are optimized, and the bonding performance, flow performance, and high-temperature resistance of the paper primer are improved.

[0036] Preferably, the tackifier is prepared by mixing tall oil rosin, gum rosin, and butyl acrylate in a weight ratio of (1-5):3:(10-15).

[0037] By adopting the above technical solution, the bonding performance of the paper primer is improved, so that the paper primer has a smooth surface after curing, and has good bonding performance with the base paper. In the present application, the above thickening agent is used to improve the affinity of the paper primer with the base paper, promote the adhesion of the paper primer, and stably connect the primer layer formed after the paper primer is cured with the base paper.

[0038] Preferably, the solid content of the polyvinyl acetate in the polyvinyl acetate emulsion is 30-60%, and the molecular weight of the polyvinyl acetate is 20000-50000.

[0039] By adopting the above technical solution, the parameters of the polyvinyl acetate emulsion are optimized, so that the paper primer has good flow performance and good bonding stability. If the solid content of the polyvinyl acetate in the polyvinyl acetate emulsion is too high, the polyvinyl acetate emulsion and the styrene-acrylate emulsion will be difficult to mix uniformly, and the smoothness and flatness of the primer layer formed will be reduced. If the solid content of the polyvinyl acetate in the polyvinyl acetate emulsion is too low, the bonding performance of the paper primer will be reduced.

[0040] Preferably, the leveling agent includes one of isophorone, diacetone alcohol, phosphate-modified acrylic leveling agent, polydimethylsiloxane, polymethylalkylsiloxane, or organically modified polysiloxane.

[0041] By adopting the above technical solution, the flowability of the paper primer is improved. In the present application, the polyvinyl acetate emulsion and the styrene-acrylate emulsion are used to prepare the paper primer, so that the flowability of the paper primer is limited. By comparison, the above leveling agent is added to the paper primer, so that the flowability of the paper primer is improved, and the paper primer is convenient to coat. And the paper primer is promoted to form a smooth, flat, and uniform primer layer after curing.

[0042] In a second aspect, the present application provides a preparation method of a paper primer, which adopts the following technical solution:

[0043] A preparation method of a paper primer, comprising the following preparation steps.

[0044] S1, according to parts by weight, the styrene-acrylate emulsion, leveling agent, tackifier and wetting agent are mixed and stirred, and the stirring is stopped after, to obtain mixture A;

[0045] S2, according to parts by weight, the polyvinyl acetate emulsion, water and emulsifier are mixed and stirred, and the stirring is stopped after, to obtain mixture B;

[0046] S3, according to parts by weight, mixture A, mixture B and curing agent are mixed and stirred, to obtain the paper primer.

[0047] By adopting the above technical scheme, the paper primer with uniform dispersity and stable system is obtained. The compatibility of the styrene-acrylate emulsion and the polyvinyl acetate emulsion is poor, and direct mixing will cause the paper primer to be layered, and the flatness and smoothness of the primer layer formed are poor. In view of this, the styrene-acrylate emulsion, the leveling agent, the tackifier and the wetting agent are mixed and stirred to prepare mixture A, the polyvinyl acetate emulsion, water and the emulsifier are mixed and stirred to prepare mixture B, and then mixture A, mixture B and the curing agent are mixed, so as to solve the problem of poor compatibility of the styrene-acrylate emulsion and the polyvinyl acetate emulsion, and thus the paper primer with good bonding performance and good fluidity is obtained.

[0048] In summary, the present application has the following beneficial effects:

[0049] 1, the present application prepares the paper primer by using polyvinyl acetate emulsion, styrene-acrylate emulsion, leveling agent, tackifier, wetting agent, water, emulsifier and curing agent, and the paper primer has good fluidity, can be uniformly coated on the surface of ordinary paper, forms a smooth and flat primer layer, is conducive to subsequent aluminum plating operation, reduces the phenomenon of color explosion and ashing of aluminum-plated composite paper caused by uneven primer layer. At the same time, the selectivity of the paper primer in the present application to paper is not strong, and special base paper does not need to be used, which can further reduce the production cost of enterprises. In addition, the polyvinyl acetate emulsion and the styrene-acrylate emulsion in the present application can improve the high temperature resistance of the paper primer, which is conducive to the aluminum plating of the primer layer.

[0050] 2, the present application prepares modified styrene-acrylate emulsion by using styrene-acrylate emulsion, polyvinyl alcohol, silicone modified acrylate emulsion, silane coupling agent, Tween, water and nano silicon dioxide, which can improve the compatibility of the styrene-acrylate emulsion and the polyvinyl acetate emulsion, form a uniform paper primer system, and is conducive to forming a smooth and flat primer layer. DETAILED DESCRIPTION

[0051] EMBODIMENT

[0052] EMBODIMENT 1

[0053] A paper primer is prepared by the following method:

[0054] S1, polyvinyl acetate emulsion 0.40Kg, leveling agent 0.01Kg (isophorone), tackifier 0.02Kg (dicyclopentadiene petroleum resin) and wetting agent 0.05Kg (polyether modified polysiloxane) are mixed and stirred to obtain mixture A;

[0055] S2, styrene-acrylate emulsion 0.10Kg, water 0.20Kg and emulsifier 0.6Kg (sodium dodecyl sulfate) are mixed and stirred to obtain mixture B;

[0056] S3, mixture A, mixture B and curing agent 0.01Kg (coconut amine) are mixed and stirred to obtain the paper primer.

[0057] The styrene-acrylate emulsion has a Tg value of -10℃, an acid value of 30mgKOH / g, a solid content of 40%, and a viscosity of 500mPa·s.

[0058] The solid content of polyvinyl acetate in the polyvinyl acetate emulsion is 30%, and the molecular weight of the polyester vinyl acetate is 40000.

[0059] The molecular weight of the polyether modified polysiloxane is 5000, and the viscosity is 1500mPa·s at 25℃.

[0060] Example 2-3 and Example 1 differ in that the original kind and amount of the paper primer are different, and the rest of the test steps are the same, and the specific differences are shown in Table 1:

[0061] Table 1 Original kind and amount of paper primer prepared in Examples 1-3

[0062]

[0063]

[0064] The molecular weight of the polyester modified polysiloxane is 6000, and the viscosity is 2000mPa·s at 25℃.

[0065] Example 4

[0066] A paper primer, the difference between this embodiment and Example 1 is that the styrene-acrylate emulsion is a modified styrene-acrylate emulsion, and the rest of the raw material kind, amount and test steps are consistent with Example 1.

[0067] The modified styrene-acrylate emulsion is prepared by the following method:

[0068] 1) 0.05 Kg of polyvinyl alcohol and 0.20 Kg of water were added into a reaction kettle and stirred, then 0.20 Kg of styrene-acrylate emulsion was added, and after stirring, a milky white pre-emulsion was obtained;

[0069] 2) 0.10 Kg of silicone-modified acrylate emulsion, 0.01 Kg of silane coupling agent (vinyl tri(methoxyethoxy) silane), 0.02 Kg of Tween and 0.02 Kg of nano-silica were mixed, high-speed stirring was performed, the milky white pre-emulsion was added, and stirring was performed until the viscosity was 3000-8000 mPa·s, to obtain a modified styrene-acrylate emulsion.

[0070] Example 5-6 differs from Example 4 in that the types, amounts and experimental parameters of the raw materials for preparing the modified styrene-acrylate emulsion are different from those of Example 4, and the specific differences in Examples 4-6 are shown in Table 2:

[0071] Table 2 Types, amounts and experimental steps for preparing the modified styrene-acrylate emulsion in Examples 4-6

[0072]

[0073]

[0074] Example 7

[0075] A paper primer, which differs from Example 1 in that the styrene-acrylate emulsion is a film-forming emulsion with a Tg value of -30℃, an acid value of 20 mgKOH / g, a solid content of 60%, and a viscosity of 2000 mPa·s, and the types, amounts and experimental steps of the remaining raw materials are consistent with those of Example 1.

[0076] Example 8

[0077] A paper primer, which differs from Example 1 in that the solid content of polyvinyl acetate in the polyvinyl acetate emulsion is 20%, and the molecular weight of the polyester vinyl acetate is 55000, and the types, amounts and experimental steps of the remaining raw materials are consistent with those of Example 1.

[0078] Example 9

[0079] A paper primer, which differs from Example 1 in that the weight ratio of the polyvinyl acetate emulsion to the styrene-acrylate emulsion is 50:10, the polyvinyl acetate emulsion is 0.50 Kg, and the styrene-acrylate emulsion is 0.10 Kg, and the types, amounts and experimental steps of the remaining raw materials are consistent with those of Example 1.

[0080] Example 10

[0081] A paper primer adhesive, different from Example 4 in that the weight ratio of polyvinyl acetate emulsion to styrene-acrylate emulsion is 55:10, the polyvinyl acetate emulsion is 0.55 Kg, the styrene-acrylate emulsion is 0.10 Kg, and the rest of the raw material types, amounts and test procedures are the same as Example 4.

[0082] Example 11

[0083] A paper primer adhesive, different from Example 1 in that the tackifier is prepared by mixing tall oil rosin, gum rosin and butyl acrylate according to a weight ratio of 1:3:10, the tall oil rosin is 0.0014 Kg, the gum rosin is 0.0043 Kg and the butyl acrylate is 0.01428 Kg, and the rest of the raw material types, amounts and test procedures are the same as Example 1.

[0084] The gum rosin has a softening point of 96°C and a relative density of 1.15.

[0085] The tall oil rosin has a rosin acid content of 1.8% and an acid value of 200 mgKOH / g.

[0086] Example 12

[0087] A paper primer adhesive, different from Example 4 in that the tackifier is prepared by mixing tall oil rosin, gum rosin and butyl acrylate according to a weight ratio of 5:3:11, the tall oil rosin is 0.0071 Kg, the gum rosin is 0.0043 Kg and the butyl acrylate is 0.1571 Kg, and the rest of the raw material types, amounts and test procedures are the same as Example 4.

[0088] The gum rosin has a softening point of 96°C and a relative density of 1.15.

[0089] The tall oil rosin has a rosin acid content of 1.8% and an acid value of 200 mgKOH / g.

[0090] Comparative Example

[0091] Comparative Example 1

[0092] A paper primer adhesive, different from Example 1 in that a cyclic anhydride resin adhesive is used instead of an equal amount of polyvinyl acetate emulsion, and the rest of the raw material types, amounts and test procedures are the same as Example 1.

[0093] The cyclic anhydride resin adhesive has a relative molecular weight of 5000 and a viscosity of 18000 mPa.s at 25°C.

[0094] Comparative Example 2

[0095] A paper primer adhesive, the difference between this embodiment and Example 1 is that epoxy resin adhesive is used instead of equal mass of styrene-acrylate emulsion, the rest of the raw material types, amount and test steps are consistent with Example 1.

[0096] The relative molecular weight of the epoxy resin adhesive is 5000, and the viscosity is 18000 mPa.s at 25°C.

[0097] Comparative Example 3

[0098] A paper primer adhesive, the difference between this embodiment and Example 1 is that butyl acrylate is used instead of equal mass of styrene-acrylate emulsion, the rest of the raw material types, amount and test steps are consistent with Example 1.

[0099] Comparative Example 4

[0100] A paper primer adhesive, the difference between this embodiment and Example 1 is that butyl acrylate is used instead of equal mass of polyvinyl acetate emulsion, the rest of the raw material types, amount and test steps are consistent with Example 1.

[0101] Comparative Example 5

[0102] A paper primer adhesive, the difference between this embodiment and Example 1 is that styrene-acrylate emulsion 0.60Kg, leveling agent 0.01Kg (isophorone), tackifier 0.02Kg (dicyclopentadiene petroleum resin), wetting agent 0.05Kg (polyether modified polysiloxane) polyvinyl acetate emulsion 0.10Kg, water 0.20Kg, emulsifier 0.60Kg (sodium dodecyl sulfate) and curing agent 0.01Kg (coconut amine) are mixed and stirred to obtain a paper primer adhesive.

[0103] Performance test

[0104] The paper primer adhesives prepared in Examples 1-12 and Comparative Examples 1-5 are tested for flatness and smoothness after curing, and adhesion stability.

[0105] Detection method / test method

[0106] Flatness and smoothness test after curing: 17 base papers are selected, the base paper is purchased from Guangzhou Jumeng Trade Co., Ltd., the material is 100% virgin pulp, and the thickness is 0.5mm. The paper primer adhesives prepared in Examples 1-12 and Comparative Examples 1-5 are coated on the surface of the base paper, and the coating amount is 20g / m 2The paper coated with the primer adhesive of Example 1 was dried and cured to form a primer layer, and the primer layer was tested for flatness and smoothness. The primer layer formed by the paper coated with the primer adhesive of Examples 1-12 and Comparative Examples 1-5 was measured for gloss using a gloss meter, the brand of which was ColorP, and the model was DG60 SE / Pro / MAX. The smoother the surface of the primer layer, the stronger the mirror reflection of light, and the higher the gloss. Conversely, the lower the gloss.

[0107] In addition, a special aluminum-plated paper with a tightness of 100 (g / cm3), a burst resistance of 100%, and a thickness of 0.5 mm was selected, and the paper coated with the primer adhesive of Example 1 was coated on the surface of the special aluminum-plated paper at a coating amount of 20 g / m 2 The paper was dried and cured to form a primer layer, and the primer layer was tested for flatness and smoothness, which was Comparative Example 6.

[0108] In addition, another base paper was selected, which was purchased from Shenzhen Shenjincheng New Material Co., Ltd., and the grade was first grade. The paper coated with the primer adhesive of Example 1 was coated on the surface of the base paper at a coating amount of 20 g / m 2 The paper was dried and cured to form a primer layer, and the primer layer was tested for flatness and smoothness, which was Comparative Example 7.

[0109] Adhesion stability test: the base paper with the primer adhesive prepared in Examples 1-12 and Comparative Examples 1-7 was vacuum aluminum-plated at a vacuum degree of 12 mba and a temperature of 200°C. After the aluminum plating was completed, whether the composite paper after the aluminum plating had phenomena such as ashing, bubbling, and color explosion was observed, and an adhesion test was performed.

[0110] Adhesion test: 100 grids were scratched in 1 cm*1 cm, and 3M tape was tightly pasted on the surface of the aluminum-plated layer at 90°, and the tape was quickly torn off, and the number of damaged grids was calculated.

[0111] The test data are shown in Table 3.

[0112] Table 3 Performance test data

[0113]

[0114] From Examples 1-12 and Comparative Examples 1-7 and in combination with Table 3, it can be seen that the paper primer adhesive prepared in the present application has good adhesion and can be used for general paper, and after forming a primer layer, the surface is smooth and flat, which is conducive to the operation of aluminum plating. In addition, the paper primer adhesive prepared in the present application has good temperature resistance, and can adapt to 200-400°C, and does not appear uneven or bubbling at this temperature.

[0115] Compared with Comparative Example 1, the glossiness of Example 1 is higher than that of Comparative Example 1, the number of damaged grids in the adhesive stability test of Comparative Example 1 is greater than that of Example 1, and Comparative Example 1 appears ash at 200℃ and appears ash with bubbles at 400℃, which shows that the paper bottom coating adhesive prepared by using the polyvinyl acetate emulsion, the styrene-acrylate emulsion, the leveling agent, the tackifier, the wetting agent, the water, the emulsifier and the curing agent together can form a smooth and flat bottom coating layer on the surface of the base paper, and has good adhesion.

[0116] Compared with Example 1, Comparative Example 2 appears ash at 200℃, appears ash with bubbles at 400℃ and the number of damaged grids is greater than that of Example 1, which shows that the addition of the styrene-acrylate emulsion in the application can effectively improve the temperature resistance of the paper bottom coating adhesive, and also can form a smooth and flat bottom coating layer at high temperature.

[0117] Compared with Comparative Examples 3-4, the glossiness of Example 1 is higher than that of Comparative Examples 3-4, the number of damaged grids in the adhesive stability test of Comparative Examples 3-4 is greater than that of Example 1, and Comparative Examples 3-4 appear color explosion at 200℃ and also appear color explosion at 400℃, which shows that the use of the polyvinyl acetate emulsion and the styrene-acrylate emulsion together can improve the glossiness, the adhesive stability and the high temperature resistance of the paper bottom coating adhesive.

[0118] Compared with Comparative Example 5, the glossiness of Example 1 is higher than that of Comparative Example 5, the number of damaged grids in the adhesive stability test of Comparative Example 5 is greater than that of Example 1, and Comparative Example 5 appears color explosion at 200℃ and also appears color explosion at 400℃, which shows that the paper bottom coating adhesive prepared by the preparation method of the application has good glossiness and strong adhesive stability.

[0119] Compared with Comparative Examples 6-7, it shows that the paper bottom coating adhesive prepared in the application can adapt to different types of base paper, and can form a bottom coating layer with good glossiness and strong adhesive stability.

[0120] Compared with Examples 4-6, the glossiness of Example 1 is lower than that of Examples 4-6, and the adhesive stability is lower than that of Examples 4-6, which shows that the use of the modified styrene-acrylate emulsion prepared in the application can improve the glossiness, the high temperature resistance and the adhesive stability of the paper bottom coating adhesive.

[0121] The specific embodiments are only an explanation of the application, and are not a limitation of the application, and those skilled in the art can make modifications to the embodiments without creative contribution after reading the specification, but as long as the modifications are within the scope of the claims of the application, they are protected by the patent law.

Claims

1. A paper primer gum, characterized by, The paper primer glue is prepared from the following raw materials in parts by weight: Polyvinyl acetate emulsion 40-60 parts Styrene-acrylate emulsion 10-20 parts Leveling agent 1-5 parts Tackifier 2-4 parts Wetting agent 5-10 parts Water 10-20 parts Emulsifier 2-4 parts Curing agent 1-2 parts. The styrene-acrylate emulsion is a modified styrene-acrylate emulsion prepared by the following method: 1) Polyvinyl alcohol and water are added to a reaction kettle and stirred, then styrene-acrylate emulsion is added, and after stirring, a milky white pre-emulsion is obtained; 2) The silicone-modified acrylate emulsion, silane coupling agent, Tween, and nano-silica are mixed and stirred at high speed, and the milky white pre-emulsion is added and stirred to a viscosity of 3000-8000 mPa·s to obtain a modified styrene-acrylate emulsion; The parts by weight of the raw materials used to prepare the modified styrene-acrylate emulsion are as follows: Styrene-acrylate emulsion 20-30 parts Polyvinyl alcohol 5-10 parts Silicone-modified acrylate emulsion 10-20 parts Silane coupling agent 1-3 parts Tween 2-4 parts Water 20-40 parts Nano-silica 2-5 parts.

2. A paper primer adhesive according to claim 1, characterized by: The solid content of the silicone-modified acrylate emulsion is 40-50%, and the number average molecular weight of the silicone-modified acrylate is 40-150 thousand.

3. A paper primer adhesive according to claim 1, characterized by: The styrene-acrylate emulsion has a Tg value of -10-5℃, an acid value of 30-50 mgKOH / g, a solid content of 40-50%, and a viscosity of 500-3000 mPa·s.

4. A paper primer adhesive according to claim 3, characterized by: The weight ratio of the polyvinyl acetate emulsion to the styrene-acrylate emulsion is (50-55):

10.

5. A paper primer adhesive according to claim 1, characterized by: The tackifier is prepared by mixing tall oil rosin, coumarone resin, and butyl acrylate in a weight ratio of (1-5):3:(10-15).

6. A paper primer adhesive according to claim 1, characterized by: The solid content of the polyvinyl acetate in the polyvinyl acetate emulsion is 30-60%, and the molecular weight of the polyester vinyl acetate is 20,000-50,000.

7. A paper primer adhesive according to claim 1, characterized by: The leveling agent includes one of isophorone, diacetone alcohol, phosphate-modified acrylic leveling agent, polydimethylsiloxane, polymethylalkylsiloxane, or organically modified polysiloxane.

8. A process for the production of a paper primer adhesive according to any one of claims 1 to 7, characterised in that, The preparation steps include: S1, according to the parts by weight, the styrene-acrylate emulsion, leveling agent, tackifier, and wetting agent are mixed and stirred to obtain a mixture A; S2, according to the parts by weight, the polyvinyl acetate emulsion, water, and emulsifier are mixed and stirred to obtain a mixture B; S3, according to the parts by weight, the mixture A, the mixture B, and the curing agent are mixed and stirred to obtain the paper primer glue.

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