A solvent-free type silicone release agent and a preparation method thereof

Abstract

The present application provides a kind of solvent-free type silicone release agent and its preparation method.The release agent comprises: vinyl polysiloxane, inhibitor, hydrogen-containing silicone oil, inflatable porous microspheres, catalyst, wherein the inflatable porous microspheres are treated by corona.The release agent can form a layer of porous expanded microsphere structure on the surface after curing under heat, the specific surface area sharply increases, and the unit contact area with the pasted object greatly reduces, thereby reducing the silicon transfer.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of silicone, and particularly relates to a solvent-free silicone release agent and a preparation method thereof. BACKGROUND

[0002] The solvent-free silicone release agent is a kind of anti-sticking agent which can be coated on the surface of substrates such as paper and film, and is mainly used in combination with some adhesive substances to achieve the purpose that the adhesive substances can be easily separated from the surface of the substrates, and is commonly used in the industries of labels, adhesive tapes and food baking.

[0003] The solvent-free silicone release agent is a kind of release agent with multiple advantages: no solvent in the system, environmentally friendly, wide range of peel force (1-1000 g / inch), long-term stable peel force, low silicon transfer, and little influence on the pasted objects.

[0004] The solvent-free silicone release agent is generally composed of vinyl-containing polysiloxane, inhibitor, hydrogen-containing silicone oil, expandable porous microspheres and catalyst. Among them, the main component is vinyl-containing polysiloxane, which provides the vinyl functional group required for crosslinking reaction; the inhibitor is alkyne alcohol, which can ensure that the release agent has a long bath time at room temperature (20-40℃); the crosslinking agent is hydrogen-containing silicone oil, which provides the silicon hydrogen functional group required for crosslinking reaction; the expandable porous microspheres are microparticles made of acrylic acid polymer, and the surface is treated by corona treatment, which has the characteristics of lightness, porosity and foaming.

[0005] The surface of the ordinary expanded microspheres is relatively sparse, and after expansion by heating, it cannot achieve the effect of expansion and foaming, that is, it does not have a high specific surface area. In addition, the currently marketed expanded microspheres are mostly polyolefin materials such as PE and PP, which are easily expanded by heating and easily collapsed under stress after cooling. SUMMARY

[0006] One of the purposes of the present application is to provide a solvent-free silicone release agent, which can form a layer of porous expanded microsphere structure on the surface after curing by heating, the specific surface area is sharply increased, and the unit contact area with the pasted object is greatly reduced, so that the silicon transfer is reduced.

[0007] In order to achieve the above-mentioned purposes of the application, the technical scheme adopted by the present application is as follows:

[0008] A solvent-free silicone release agent, which is prepared from raw materials containing the following mass proportions:

[0009] 100 parts of vinyl-containing polysiloxane;

[0010] 0.005-0.05 parts of an inhibitor;

[0011] 0.5-5.0 parts of hydrogen-containing silicone oil;

[0012] 0.5-10.0 parts of expandable porous microspheres;

[0013] 1.0-5.0 parts of catalyst.

[0014] The inventors have found that by introducing expandable porous microspheres and subjecting the surface of the expandable porous microspheres to corona treatment, a dense and fine pore structure is formed on the surface of the expandable porous microspheres. The expandable porous microspheres not only have a high specific surface area by themselves, but also greatly reduce the surface contact area when spread on the surface of a substrate. In addition, the expandable porous microspheres have the characteristics of being porous and foaming, and will expand with an increase in temperature, and the degree of expansion is controlled by temperature, so that the degree of foaming can be controlled by the curing temperature to achieve the lowest specific surface area, thereby achieving the lowest silicon transfer effect.

[0015] In one embodiment of the present application, the mass percentage of vinyl groups in the polysiloxane of ethylene is 0.1% to 2.0%, preferably 0.3% to 1.2%.

[0016] In one embodiment of the present application, the inhibitor is an acetylenic alcohol inhibitor, preferably one or more of ethynylcyclohexanol, dimethylhexyne alcohol, methylbutyne alcohol, and methylacetylene alcohol.

[0017] In one embodiment of the present application, the content of hydrogen in the hydrogen-containing silicone oil is 0.6 to 2.0 wt%, and the preferred content of hydrogen is 1.0 to 1.6 wt%. The viscosity of the hydrogen-containing silicone oil at 25°C is 10 to 100 mPa-s, and more preferably 15 to 50 mPa-s.

[0018] In one embodiment of the present application, the expandable porous microspheres are microparticles made of a polymer, preferably microparticles made of acrylic acid.

[0019] In one embodiment of the present application, the expandable porous microspheres are subjected to corona treatment; preferably, the particle size of the expandable porous microspheres ranges from 5 to 150 μm, and more preferably from 10 to 70 μm; preferably, the true density of the expandable porous microspheres ranges from 0.05 to 1.00 g / cm3, and more preferably from 0.10 to 0.70 g / cm3; and preferably, the specific surface area of the expandable porous microspheres is 5 to 70 m2 / g, and more preferably 10 to 50 m2 / g.

[0020] In one embodiment of the present application, the catalyst is selected from metal catalysts, preferably platinum gold catalysts, and the platinum gold content is 3000 ppm to 10000 ppm.

[0021] Another object of the present application is to provide a method for preparing a solvent-free type silicone release agent.

[0022] A method for preparing a solvent-free type silicone release agent, the method for preparing the above-mentioned silicone release agent, the method comprising the following steps:

[0023] P1: corona treatment of expandable porous microspheres;

[0024] P2: mixing the vinyl-containing polysiloxane, the inhibitor, the hydrogen-containing silicone oil and the corona-treated expandable porous microspheres, adding a catalyst and stirring to obtain a release agent.

[0025] In an embodiment of the present application, the corona treatment in P1 uses plasma corona treatment; preferably, the parameters of the corona treatment are: power 500-800 W, flame temperature 40-50℃, input gauge pressure 0.4-0.5 MPa, and corona treatment time 10-15 min.

[0026] Compared with the prior art, the present application has the following beneficial effects:

[0027] (1) The corona treatment step is simple and easy to operate;

[0028] (2) The specific surface area of the expanded microspheres after corona treatment is greatly improved, and good silicon transfer effect can be obtained when applied in a release agent;

[0029] (3) The expanded microspheres after corona treatment are suitable for coating various paper and film substrates. DETAILED DESCRIPTION

[0030] The technical solutions of the present application will be described below in conjunction with specific examples, which are used to explain the present application and not to limit the scope of the present application.

[0031] Raw materials and sources:

[0032] Vinyl-containing polysiloxane, HS-350, vinyl content 0.50%, Huisi Silicon Industry Co., Ltd.;

[0033] Vinyl-containing polysiloxane, HS-220, vinyl content 0.95%, Huisi Silicon Industry Co., Ltd.;

[0034] Inhibitor, ethynylcyclohexanol, Araldine, analytical pure;

[0035] Inhibitor, methylbutynol, Araldine, analytical pure;

[0036] Hydrogen-containing silicone oil, RH-H510, silicon hydrogen content 1.0%, Ningbo Runhe High-tech Material Technology Co., Ltd.;

[0037] Hydrogen-containing silicone oil, RH-H516, silicon hydrogen content 1.6%, Ningbo Runhe High-tech Material Technology Co., Ltd.;

[0038] Platinum catalyst, HLS 3000, 3000 ppm content, Heraeus;

[0039] Platinum catalyst, HLS 5000, 5000 ppm content, Heraeus;

[0040] Expandable porous microspheres: acrylic material, 120 DU25, particle size 20-30 pm, vacuum degree 0.5-0.7 g / cm 3 , specific surface area 20-40 m 2 / g, POLYCHEM, industrial product;

[0041] Expandable porous microspheres: acrylic material, 200 DU35, particle size 50-70 pm, vacuum degree 0.4-0.6 g / cm 3 , specific surface area 30-50 m 2 / g, POLYCHEM, industrial product;

[0042] Expandable porous microspheres: acrylic material, Expancel 920MB120, particle size 120-150 pm, vacuum degree 0.5-0.7 g / cm 3 , specific surface area 30-50 m 2 / g, Nolinge, industrial product;

[0043] Expandable porous microspheres: polystyrene material, PS020000, particle size 20-30 pm, vacuum degree 0.5-0.7 g / cm 3 , specific surface area 20-40 m 2 / g, Zhongke Leiming, industrial product.

[0044] Plasma corona machine: KRF-5-1, Shenzhen Jinputailai Technology.

[0045] Peeling force: 180° tensile machine, standard 7475 tape, width 25 mm.

[0046] Residual adhesion: 180° tensile machine, standard 31B tape, width 25 mm.

[0047] Aging condition: aging in a 70°C oven for 20 h.

[0048] Preparation Example 1

[0049] Plasma corona treatment: power: 500 W, flame temperature: 40°C, input gas pressure: 0.4 MPa, corona time 10 min, expanded microspheres 120 DU25 after corona treatment are recorded as S1.

[0050] Preparation Example 2

[0051] Plasma corona treatment: power: 800 W, flame temperature: 50°C, input gas pressure: 0.5 MPa, corona time 15 min, the expanded microspheres 120DU25 after corona treatment are recorded as S2.

[0052] Preparation Example 3

[0053] Plasma corona treatment: power: 600 W, flame temperature: 45°C, input gas pressure: 0.45 MPa, corona time 13 min, the expanded microspheres 200DU35 after corona treatment are recorded as S4.

[0054] Preparation Example 4

[0055] Plasma corona treatment: power: 600 W, flame temperature: 45°C, input gas pressure: 0.45 MPa, corona time 13 min, the expanded microspheres 200DU35 after corona treatment are recorded as S4.

[0056] Preparation Example 5

[0057] Plasma corona treatment: power: 600 W, flame temperature: 45°C, input gas pressure: 0.45 MPa, corona time 13 min, the expanded microspheres Expancel 920MB120 after corona treatment are recorded as S5.

[0058] Preparation Example 6

[0059] Plasma corona treatment: power: 600 W, flame temperature: 45°C, input gas pressure: 0.45 MPa, corona time 13 min, the expanded microspheres PS020000 after corona treatment are recorded as S6.

[0060] Example 1

[0061] A glass cup is added with 100 g of vinyl-containing polysiloxane, HS-350, 0.010 g of dimethylacetylene alcohol, 2.6 g of hydrogen-containing silicone oil, RH-H510, 2.0 g of expandable porous microspheres S1, and stirred for 30 min; 1.0 g of platinum gold catalyst, HSL 5000, is slowly added dropwise to the above mixture, stirred for 20 min, and finally the desired release agent is prepared.

[0062] Example 2

[0063] A glass cup is added with 100 g of vinyl-containing polysiloxane, HS-220, 0.030 g of methylbutynol, 2.2 g of hydrogen-containing silicone oil, RH-H516, 2.0 g of expandable porous microspheres S2, and stirred for 30 min; 4.0 g of platinum gold catalyst, HSL 3000, is slowly added dropwise to the above mixture, stirred for 20 min, and finally the desired release agent is prepared.

[0064] Example 3

[0065] A glass beaker was charged with 100 g of vinyl-containing polysiloxane, HS-350, 0.020 g of dimethylacetylene alcohol, 2.6 g of hydrogen-containing silicone oil, RH-H510, 2.0 g of expandable porous microspheres S3, and stirred for 30 min. To the above mixture, 1.5 g of platinum gold catalyst, HLS 5000, was added dropwise slowly, and stirred for 20 min, and finally the desired release agent was prepared.

[0066] Example 4

[0067] A glass beaker was charged with 100 g of vinyl-containing polysiloxane, HS-350, 0.020 g of dimethylacetylene alcohol, 2.6 g of hydrogen-containing silicone oil, RH-H510, 1.0 g of expandable porous microspheres S3, and stirred for 30 min. To the above mixture, 1.5 g of platinum gold catalyst, HLS 5000, was added dropwise slowly, and stirred for 20 min, and finally the desired release agent was prepared.

[0068] Example 5

[0069] A glass beaker was charged with 100 g of vinyl-containing polysiloxane, HS-350, 0.020 g of dimethylacetylene alcohol, 2.6 g of hydrogen-containing silicone oil, RH-H510, 4.0 g of expandable porous microspheres S3, and stirred for 30 min. To the above mixture, 1.5 g of platinum gold catalyst, HLS 5000, was added dropwise slowly, and stirred for 20 min, and finally the desired release agent was prepared.

[0070] Example 6

[0071] A glass beaker was charged with 100 g of vinyl-containing polysiloxane, HS-350, 0.020 g of dimethylacetylene alcohol, 2.6 g of hydrogen-containing silicone oil, RH-H510, 2.0 g of expandable porous microspheres S4, and stirred for 30 min. To the above mixture, 1.5 g of platinum gold catalyst, HLS 5000, was added dropwise slowly, and stirred for 20 min, and finally the desired release agent was prepared.

[0072] Example 7

[0073] A glass beaker was charged with 100 g of vinyl-containing polysiloxane, HS-350, 0.020 g of dimethylacetylene alcohol, 2.6 g of hydrogen-containing silicone oil, RH-H510, 2.0 g of expandable porous microspheres S5, and stirred for 30 min. To the above mixture, 1.5 g of platinum gold catalyst, HLS 5000, was added dropwise slowly, and stirred for 20 min, and finally the desired release agent was prepared.

[0074] Example 8

[0075] A glass beaker was charged with 100 g of vinyl-containing polysiloxane, HS-350, 0.020 g of dimethylacetylene alcohol, 2.6 g of hydrogen-containing silicone oil, RH-H510, 2.0 g of expandable porous microspheres, S6, and stirred for 30 min. To the mixture, 1.5 g of platinum-gold catalyst, HLS 5000, was added dropwise, and stirred for 20 min. The desired release agent was finally prepared.

[0076] Comparative Example 1

[0077] Comparing with Example 3, the difference is that the expandable porous microspheres are not treated by plasma corona.

[0078] A glass beaker was charged with 100 g of vinyl-containing polysiloxane, HS-350, 0.020 g of dimethylacetylene alcohol, 2.6 g of hydrogen-containing silicone oil, RH-H510, 2.0 g of expandable porous microspheres, 120DU25, without corona treatment, and stirred for 30 min. To the mixture, 1.5 g of platinum-gold catalyst, HLS 5000, was added dropwise, and stirred for 20 min. The desired release agent was finally prepared.

[0079] The obtained release agent was uniformly coated on 58 g of UPM Glassine, and the curing conditions were 140°C*15s, and the coating amount was 1.2 gsm. The obtained silicone release agent coating was subjected to residual adhesion and aging release force tests, and the specific results were as follows:

[0080]

[0081] From Examples 1, 2 and 3, it can be seen that the residual adhesion and aging release force of the release agent coating prepared from the raw materials within the parameter range of the present patent claim are comparable, and the parameter range of the raw materials is all within the effective range;

[0082] From Examples 3 and 4, 5, it can be seen that when the addition amount of S3 is 2.0 g, the residual adhesion and aging release force of the prepared release agent coating are best;

[0083] From Examples 3 and 6, 7, it can be seen that the expandable microspheres treated by corona within the parameter range of the present patent claim can all obtain excellent residual adhesion and aging release force performance;

[0084] From Examples 3 and 8, it can be seen that the expandable microspheres of acrylic material and the expandable microspheres of polystyrene material have comparable residual adhesion and aging release force performance;

[0085] From Examples 3 and Comparative Example 1, it can be seen that compared with the expandable microspheres without corona treatment, the residual adhesion and aging release force of the expandable porous microspheres treated by corona are greatly improved.

[0086] In summary, the expandable porous microspheres after corona treatment can obtain excellent residual adhesive force and aging peeling force performance, that is, residual adhesive force > 92.0%, and aging peeling force < 6 g / inch.

[0087] Those skilled in the art can understand that, under the teaching of the present specification, some modifications or adjustments can be made to the present application. These modifications or adjustments should also be within the scope defined by the claims of the present application.

Claims

1. A solvent-free silicone release agent, characterized in that, The release agent is prepared from raw materials comprising the following mass proportions: 100 parts of vinyl-containing polysiloxane; 0.005–0.05 parts inhibitor; 0.5–5.0 parts of hydrogen-containing silicone oil; 0.5–10.0 parts expandable porous microspheres; 1.0–5.0 parts catalyst; The vinyl content in the ethylene-containing polysiloxane is 0.1% to 2.0% by mass. The hydrogen content in the hydrogen-containing silicone oil is 0.6–2.0 wt%. The expandable porous microspheres have porous and foaming properties and expand as the temperature rises; the expandable porous microspheres are treated with corona discharge.

2. The release agent as described in claim 1, characterized in that, The vinyl content in the ethylene-containing polysiloxane is 0.3% to 1.2% by mass.

3. The release agent as described in claim 1 or 2, characterized in that, The inhibitor is an alkynol inhibitor.

4. The release agent as described in claim 3, characterized in that, The inhibitor is one or more of ethynylcyclohexanol, dimethylhexynol, methylbutynol, and methylethynol.

5. The release agent as described in claim 1 or 2, characterized in that, The hydrogen content in the hydrogen-containing silicone oil is 1.0 to 1.6 wt%.

6. The release agent as described in claim 1 or 2, characterized in that, The expandable porous microspheres are microparticles made of polymer.

7. The release agent as described in claim 6, characterized in that, The particle size range of expandable porous microspheres is 5-150 μm; The true density of expandable porous microspheres ranges from 0.05 to 1.00 g / cm³. 3 ; The specific surface area of ​​expandable porous microspheres is 10-50 m². 2 / g.

8. The release agent as described in claim 7, characterized in that, The particle size range of expandable porous microspheres is 10-70 μm; The true density of expandable porous microspheres ranges from 0.10 to 0.70 g / cm³. 3 .

9. The release agent as described in claim 1 or 2, characterized in that, The catalyst is selected from metal catalysts.

10. The release agent as described in claim 9, characterized in that, The catalyst is a platinum catalyst with a platinum content of 3000ppm to 10000ppm.

11. A method for preparing a solvent-free silicone release agent, wherein the method prepares the silicone release agent according to any one of claims 1-10, characterized in that, The method includes the following steps: P1: Corona-treated expandable porous microspheres; P2: Mix vinyl-containing polysiloxane, inhibitor, hydrogen-containing silicone oil and corona-treated expandable porous microspheres, add catalyst, and stir to obtain release agent.

12. The method as described in claim 11, characterized in that, The corona treatment in P1 uses plasma corona treatment.

13. The method as described in claim 12, characterized in that, The parameters for corona treatment are: power 500-800W, flame temperature 40-50℃, input gauge pressure 0.4-0.5MPa, and corona treatment time 10-15min.

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