A silicone release agent for coated paper and a preparation method and application thereof

Abstract

The application belongs to the technical field of silicone and release paper material, and discloses a silicone release agent for coated paper, a preparation method and application thereof. The silicone release agent for coated paper comprises the following components: 50-100 parts of end-vinyl polysiloxane, 10-30 parts of branched vinyl polysiloxane, 1-10 parts of hydrogen-containing polysiloxane, 0.1-10 parts of epoxy tackifier and 1-10 parts of platinum catalyst. The silicone release agent can be rapidly cured at low temperature of 80-130 DEG C. In addition, the addition of the self-made epoxy tackifier can significantly improve the adhesion between the release layer and the surface of the coated paper, and the coated paper can not be desiliconized for more than 10 days under the aging environment of high temperature and high humidity of 85 DEG C and 85% RH. The release paper disclosed by the application is obtained by curing the release agent on the coated paper, and solves the problems of slow curing, incomplete curing, serious post-curing, poor environmental resistance and easy desiliconization in a high temperature and high humidity environment of the existing coated release paper.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of silicone materials and release paper materials, and particularly relates to a silicone release agent for coated paper, and a preparation method and application thereof. BACKGROUND

[0002] Coated paper is a kind of paper material that polyethylene (PE) plastic particles are coated on the surface of paper through a casting machine for preliminary treatment. After coating, the coated paper has the characteristics of high temperature resistance, moisture resistance, oil leakage resistance, etc. These characteristics are beneficial to preventing silicone oil leakage after coating the silicone release agent, but due to the low melting point temperature of the PE particles on the surface of the coated paper, the coated paper cannot be cured at a temperature higher than 130 DEG C when coating the silicone release agent. In addition, the low surface energy provided by the PE particles causes poor adhesion of the release layer on the coated paper, and the release layer is easy to fall off in a high temperature and high humidity environment. If used in the printing industry, the silicone oil layer will be transferred to the face material, which will affect the subsequent printing effect. If used in the adhesive tape industry, it will cause unstable peeling force of the adhesive tape, affecting the quality of the adhesive tape. The normal temperature fast curing release agent disclosed in patent 201711384700.5 can realize low temperature fast curing, but does not contain an epoxy tackifier, and the silicone resistance of the final release paper in a high temperature and high humidity environment is not mentioned. The anchoring agent disclosed in patent 202210526521.5 can improve the adhesion of the release agent to the substrate, but the preparation technology route of the anchoring agent is complex, and the final effect is not ideal. In addition, the patent does not specifically mention the use on the coated paper. Therefore, it is necessary to prepare a new type of silicone release agent that can improve the adhesion of the release layer to the coated paper, and apply it to the preparation of release paper, which has broad application prospects. SUMMARY

[0003] In order to overcome the shortcomings of the prior art, the primary purpose of the present application is to provide a silicone release agent for coated paper. The branched vinyl polysiloxane contained in the silicone release agent can make the Si-Vi / Si-H group react completely and quickly at a temperature lower than 130 DEG C, which can avoid the problems of tearing difficulty, loud sound, etc. during unrolling of the coated paper. In addition, especially the addition of the self-made epoxy tackifier, the active groups contained therein can make the release layer firmly adhere to the coated paper. The final release paper has the characteristics of no silicone falling off for more than 10 days in a high temperature and high humidity aging environment of 85 DEG C and 85 RH, and stable release layer peeling performance.

[0004] Another purpose of the present application is to provide a preparation method of the above-mentioned silicone release agent composition.

[0005] Still another purpose of the present application is to provide an application of the above-mentioned silicone release agent composition, specifically for preparing release paper.

[0006] Another object of the present application is to provide a release paper.

[0007] The object of the present application is achieved by the following solutions:

[0008] An organic silicon release agent for coated paper, comprising the following components:

[0009] The end-vinyl polysiloxane is 50-100 parts by weight, the branched vinyl polysiloxane is 10-30 parts by weight, the hydrogen-containing polysiloxane is 1-10 parts by weight, the epoxy tackifier is 0.1-10 parts by weight, and the platinum catalyst is 1-10 parts by weight.

[0010] Preferably, the organic silicon release agent comprises the following components:

[0011] The end-vinyl polysiloxane is 60-90 parts by weight, the branched vinyl polysiloxane is 15-30 parts by weight, the hydrogen-containing polysiloxane is 2-4 parts by weight, the epoxy tackifier is 1-2 parts by weight, and the platinum catalyst is 1-2 parts by weight.

[0012] Preferably, the end-vinyl polysiloxane has a viscosity of 100-10000 mPa.s and is composed of one or several end-vinyl polysiloxanes with different molecular weights.

[0013] Preferably, the end-vinyl polysiloxane has the following structure:

[0014]

[0015] Wherein, n≥50.

[0016] The branched vinyl polysiloxane has a viscosity of 50-5000 mPa.s and contains at least 4 or more vinyl functional groups in each molecule.

[0017] Preferably, the branched vinyl polysiloxane has the following structure:

[0018]

[0019] Wherein, n1, n2, m1, m2≥1.

[0020] The hydrogen-containing polysiloxane has a viscosity of 10-500 mPa.s and contains at least 3 or more hydrogen functional groups in each molecule.

[0021] Preferably, the hydrogen-containing polysiloxane has the following structure:

[0022]

[0023] Wherein, n≥0, m>0.

[0024] Preferably, the platinum catalyst is one or more of isopropyl alcohol platinum solution, divinyltetramethyldisiloxane platinum complex, diethyl phthalate chlorohydroxypropylamine platinum complex, chloroplatinic acid-octanol complex, and the content of pt in the platinum catalyst is 800-5000 ppm.

[0025] Preferably, the structure of the epoxy adhesion promoter is as follows:

[0026]

[0027] wherein x≥0, y≥0, z≥0;

[0028] wherein R is methyl or vinyl.

[0029] Preferably, the preparation method of the epoxy adhesion promoter is as follows:

[0030] (1) three monomers, ethanol, water and catalyst are mixed and stirred to react, after the reaction is completed, a capping agent is added to continue the reaction to obtain a reaction product;

[0031] (2) the pH value of the reaction product obtained in step (1) is adjusted to 7-8, mixed and stirred, the organic layer and the inorganic layer are separated by extraction, the organic layer is washed, and the small molecule by-products of the organic layer are removed under reduced pressure to obtain the epoxy adhesion promoter;

[0032] The three monomers are γ-(2,3-epoxypropoxy) propyl methyl dimethoxysilane, methyl vinyl diethoxysilane and dimethyl dimethoxysilane.

[0033] Preferably, the reaction temperature in step (1) is 35-80℃, and the reaction time is 4-12 hours;

[0034] The continued reaction temperature in step (1) is 50-80℃, and the reaction time is 1-3 hours;

[0035] The capping agent in step (1) is one of trimethyl ethoxysilane, trimethyl methoxysilane, dimethyl vinyl methoxysilane, dimethyl vinyl ethoxysilane, 1,3-divinyl-1,1,3,3-tetramethyldisiloxane, hexamethylsilazane, etc.

[0036] The catalyst is one or more of phosphoric acid, sulfuric acid, hydrochloric acid, acetic acid, trifluoroacetic acid, triflic acid, dodecylbenzenesulfonic acid, solid acid catalyst, etc.

[0037] The pH adjustment is adding one of sodium hydroxide, sodium bicarbonate, disodium hydrogen phosphate, calcium hydroxide.

[0038] Preferably, the molar ratio of the gamma-(2,3-epoxypropoxy)propyl methyl dimethoxysilane, methyl vinyl diethoxysilane, and dimethyl dimethoxysilane in step (1) is 1:2:4, the amount of ethanol is 10-20% of the total mass of the monomers, and the amount of catalyst is 15-25% of the total mass of the monomers.

[0039] Preferably, the vacuum degree in the reduced pressure condition in step (2) is -0.09 to -0.1 MPa, and the temperature is 40-60°C.

[0040] A preparation method of a silicone release agent for coated paper, comprising the following steps:

[0041] The end-vinyl polysiloxane, branched vinyl polysiloxane, hydrogen-containing polysiloxane, and epoxy adhesion promoter are stirred uniformly in proportion, and then a platinum catalyst is added and stirred uniformly to obtain the silicone release agent.

[0042] The silicone release agent for coated paper is applied in the preparation of release paper.

[0043] Preferably, the application comprises the following steps: setting the oven curing temperature of a five-roll coater to 80-130°C and the coating speed to 30-100 M / min, pouring the silicone release agent into a roll groove to coat the coated paper, and coating the release layer on the release paper to a thickness of 0.9-1.1 g / m 2 to obtain a coated release paper.

[0044] A coated release paper is prepared by the above application.

[0045] The present application has the following advantages and beneficial effects:

[0046] (1) The release layer formed by curing the silicone release agent for coated paper has a high-temperature and high-humidity resistance of more than 10 days under an aging environment of 85°C and 85% RH, and the longest resistance can reach 25 days.

[0047] (2) The addition of the self-made epoxy adhesion promoter can significantly improve the adhesion of the release layer to the surface of the coated paper, and significantly improve the silicon resistance time.

[0048] (3) The silicone release agent of the present application can be quickly cured at a low temperature of 80-130°C, solving the problems of slow curing, incomplete curing, serious post-curing, poor environmental resistance, and easy silicon loss in a high-temperature and high-humidity environment of the existing coated release paper. BRIEF DESCRIPTION OF DRAWINGS

[0049] Figure 1 The epoxy adhesion promoter is 1 HNMR chart.

[0050] DETAILED EMBODIMENT

[0051] The present invention will be further described in detail below with reference to specific embodiments, but the implementation of the present invention is not limited thereto. For process parameters not specifically noted, conventional techniques can be referred to.

[0052] The preparation methods of the epoxy tackifiers used in Examples 1-5 are as follows:

[0053] (1) First, γ-(2,3-epoxypropoxy)propylmethyldimethoxysilane, methylvinyldiethoxysilane, and dimethyldimethoxysilane, three monomers, are added to anhydrous ethanol in a molar ratio of 1:2:4, with the amount of ethanol being 10-20% of the total mass of the monomers. Then, a 50% aqueous solution of acetic acid is added, with the amount being 15-25% of the total mass of the monomers. The reaction is stirred at 50°C for at least 6 hours. Then, 1,3-divinyl-1,1,3,3-tetramethyldisiloxane is added dropwise as a capping agent. After the addition is complete, the temperature is raised to 80°C and the reaction continues for at least 2 hours to obtain the final reaction product.

[0054] (2) Add sodium hydroxide to the above product to neutralize the excess acid until the pH of the system is 7. Add an appropriate amount of toluene to extract and separate the organic layer and the inorganic layer. Wash the organic layer collection with water more than 3 times. Finally, remove the residual small molecule byproducts under vacuum conditions of -0.09 to -0.1 MPa at 40-60℃ to obtain the epoxy tackifier. 1 See HNMR image Figure 1 .

[0055] Example 1:

[0056] 80g of terminal vinyl polysiloxane, 15g of branched vinyl polysiloxane, 3.2g of hydrogen-containing polysiloxane, and 1.0g of epoxy tackifier were mixed and stirred at room temperature until homogeneous. Then, 1.5g of platinum catalyst was added, and stirring was continued until homogeneous to obtain an organosilicon release agent composition. The release agent composition was coated onto coated paper using a five-roll coater. The speed of the feed rollers of the coater was adjusted to control the coating amount of release agent on the coated paper to be 1.0g / m². 2 The oven temperature was set at 100℃, and the coating speed was set at 42 m / min until the paper was completely surface dry.

[0057] Example 2:

[0058] A mixture of 65g terminal vinyl polysiloxane, 30g branched vinyl polysiloxane, 3.2g hydrogen-containing polysiloxane, and 1.0g epoxy tackifier was stirred at room temperature until homogeneous. Then, 1.5g platinum catalyst was added, and the mixture was stirred until homogeneous again to obtain a silicone release agent composition. This composition was then coated onto coated paper using a five-roll coater. The speed of the feed rollers of the coater was adjusted to control the amount of release agent coated on the coated paper at 1.0g / m².2 Left and right, fixed oven temperature is 100℃, according to the paper completely dry coating speed is determined to be 65M / min.

[0059] Example 3:

[0060] The end vinyl polysiloxane: 65g, branched vinyl polysiloxane: 30g, hydrogen-containing polysiloxane: 3.2g, epoxy adhesion promoter: 1.5g, mixed at room temperature, stirring uniform, then add platinum catalyst: 1.5g, continue to stir uniform, prepared silicone release agent composition, using five roll coater release agent composition coated on the film paper, adjust the feeding roll speed, control the release agent on the film paper coating amount in 1.0g / m 2 Left and right, fixed oven temperature is 100℃, according to the paper completely dry coating speed is determined to be 60M / min.

[0061] Example 4:

[0062] The end vinyl polysiloxane: 65g, branched vinyl polysiloxane: 30g, hydrogen-containing polysiloxane: 3.2g, epoxy adhesion promoter: 1.0g, mixed at room temperature, stirring uniform, then add platinum catalyst: 1.5g, continue to stir uniform, prepared silicone release agent composition, using five roll coater release agent composition coated on the film paper, adjust the feeding roll speed, control the release agent on the film paper coating amount in 1.0g / m 2 Left and right, fixed oven temperature is 100℃, according to the paper completely dry coating speed is determined to be 85M / min.

[0063] Comparative Example 1:

[0064] The end vinyl polysiloxane: 80g, hydrogen-containing polysiloxane: 3.2g, epoxy adhesion promoter: 1.0g, mixed at room temperature, stirring uniform, then add platinum catalyst: 1.5g, continue to stir uniform, prepared silicone release agent composition, using five roll coater release agent composition coated on the film paper, adjust the feeding roll speed, control the release agent on the film paper coating amount in 1.0g / m 2 Left and right, fixed oven temperature is 100℃, according to the paper completely dry coating speed is determined to be 33M / min. The comparative example with other examples different from the release agent in the main polymer is not added branched vinyl siloxane, other components and example 1 is the same.

[0065] Comparative Example 2:

[0066] vinyl polysiloxane: 65 g, branched vinyl polysiloxane: 30 g, hydrogen-containing polysiloxane: 3.2 g, and platinum gold catalyst: 1.5 g were mixed and stirred uniformly, and then an organosilicon release agent composition was prepared. The release agent composition was coated on a release paper using a five-roller coater, the speed of the feed roller of the coater was adjusted, and the coating amount of the release agent on the release paper was controlled to be 1.0 g / m 2 The temperature of the oven was fixed at 100°C, and the coating speed was determined to be 65 m / min according to the complete surface drying of the paper during coating. The comparative example is different from the other examples in that no epoxy tackifier was added to the release agent, and the other components were the same as in Example 2.

[0067] Table 1 shows the curing conditions of the release agent composition and the aging resistance of the release paper obtained in Examples 1-4 and Comparative Examples 1-2, as follows:

[0068] Table 1

[0069]

[0070]

[0071] The release paper aging resistance to silicon loss test method is as follows: after coating, the release paper sample was placed in an oven at 85°C and 85% RH, and every 2 h, the paper surface was rubbed back and forth with the index finger for no less than 30 times, and if there was no fine loss on the paper surface, it was evaluated as no silicon loss, and the paper was continued to be placed in the aging oven. The evaluation was continued until there was fine loss on the release layer, and the time was recorded, which was the aging resistance to silicon loss time of the release paper.

[0072] From the above results, under the same conditions, in Comparative Example 1, no branched vinyl polysiloxane was added, and the surface drying curing time of the paper was significantly higher than that of Example 1. As can be seen from the comparison between Examples 1 and 2, with the increase of the proportion of branched vinyl polysiloxane, the paper surface dries faster under the same temperature coating. The release layer in the high temperature and high humidity environment in Examples 1-4 with and without the addition of epoxy tackifier is higher than that in Comparative Example 2, and the aging resistance to silicon loss of the release paper in Example 2 is 5 times higher than that in Comparative Example 2.

[0073] The above examples are preferred embodiments of the present application, but the embodiments of the present application are not limited by the examples, and any changes, modifications, substitutions, combinations made without departing from the spirit and principles of the present application are equivalent replacement methods and are included in the protection scope of the present application.

Claims

1. A silicone release agent for coated paper, characterized in that, It includes the following components: By weight, 50-100 parts of terminal vinyl polysiloxane, 10-30 parts of branched vinyl polysiloxane, 1-10 parts of hydrogen-containing polysiloxane, 0.1-10 parts of epoxy tackifier, and 1-10 parts of platinum catalyst. The structural formula of the branched vinyl polysiloxane is shown below: Where: n1, n2, m1, m2≥1; The preparation method of the epoxy tackifier is as follows: (1) Mix and stir the three monomers, ethanol, water and catalyst to react. After the reaction is complete, add the end-capping agent to continue the reaction and obtain the reaction product. (2) Adjust the pH of the reaction product obtained in step (1) to 7~8, mix and stir, extract and separate the organic layer and the inorganic layer, wash the organic layer, remove the small molecule by-products of the organic layer under reduced pressure, and obtain epoxy tackifier. The three monomers are γ-(2,3-epoxypropoxy)propylmethyldimethoxysilane, methylvinyldiethoxysilane, and dimethyldimethoxysilane.

2. The silicone release agent for coated paper according to claim 1, characterized in that, The silicone release agent comprises the following components: By weight, 60-90 parts of terminal vinyl polysiloxane, 15-30 parts of branched vinyl polysiloxane, 2-4 parts of hydrogen-containing polysiloxane, 1-2 parts of epoxy tackifier, and 1-2 parts of platinum catalyst.

3. The silicone release agent for coated paper according to claim 1 or 2, characterized in that, The terminated vinyl polysiloxane has a viscosity of 100-10000 mPa·s and is composed of one or more terminated vinyl polysiloxanes with different molecular weights. The branched vinyl polysiloxane has a viscosity of 50-5000 mPa·s, and each molecule contains at least 4 or more vinyl functional groups; The hydrogen-containing polysiloxane has a viscosity of 10-500 mPa·s, and each molecule contains at least 3 or more hydrogen functional groups.

4. The silicone release agent for coated paper according to claim 1, characterized in that, The platinum catalyst is one or a combination of isopropoxide platinum solution, divinyltetramethyldisiloxane platinum complex, diethyl phthalate chlorohydroxypropylamine platinum complex, and chloroplatinic acid-octanol complex, and the content of pt in the platinum catalyst is 800-5000 ppm.

5. The silicone release agent for coated paper according to claim 1, characterized in that, The reaction temperature in step (1) is 35-80℃, and the reaction time is 4-12 hours; The reaction temperature in step (1) is 50-80℃, and the reaction time is 1-3 hours. The capping agent mentioned in step (1) is one of trimethylethoxysilane, trimethylmethoxysilane, dimethylvinylmethoxysilane, dimethylvinylethoxysilane, 1,3-divinyl-1,1,3,3-tetramethyldisiloxane, and hexamethylsilazane. The catalyst is one or more of phosphoric acid, sulfuric acid, hydrochloric acid, acetic acid, trifluoroacetic acid, trifluoromethanesulfonic acid, dodecylbenzenesulfonic acid, and solid acid catalysts.

6. A silicone release agent for coated paper according to claim 1, characterized in that, Step (1) The molar ratio of the three monomers γ-(2,3-epoxypropoxy)propylmethyldimethoxysilane, methylvinyldiethoxysilane and dimethyldimethoxysilane is 1:2:

4. The amount of ethanol is 10-20% of the total mass of the monomers, and the amount of catalyst is 15-25% of the total mass of the monomers.

7. A method for preparing an organosilicon release agent for coated paper according to any one of claims 1 to 6, characterized in that, Includes the following steps: The terminal vinyl polysiloxane, branched vinyl polysiloxane, hydrogen-containing polysiloxane, and epoxy tackifier are mixed evenly in a certain proportion, and then a platinum catalyst is added and mixed evenly to obtain the organosilicon release agent.

8. The use of the silicone release agent for coated paper according to any one of claims 1 to 6 in the preparation of release paper.

9. A type of coated release paper, characterized in that, It is prepared by the application described in claim 8.

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