Solvent-free organic silicon release agent and preparation method thereof

Abstract

The invention provides a solvent-free organic silicon release agent and a preparation method thereof. The release agent comprises vinyl polysiloxane, an inhibitor, hydrogen-containing silicone oil, expandable porous microspheres and a catalyst, wherein the expandable porous microspheres are subjected to corona treatment. The release agent can form a layer of porous expanded microsphere structure on the surface after being heated and cured, the specific surface area is sharply increased, and the unit contact area with an adhered object is greatly reduced, so that the silicon transfer is reduced.

Description

Technical Field

[0001] The invention belongs to the field of organic silicon, and specifically relates to a solvent-free organic silicon release agent and a preparation method thereof. Background Art

[0002] Solvent-free silicone release agent is an anti-sticking agent that can be applied to the surface of substrates such as paper and film. It is mainly used in combination with some adhesive substances to achieve the purpose of easily separating the adhesive substances from the surface of the substrate. It is commonly used in industries such as labels, tapes, and food baking.

[0003] Solvent-free silicone release agent is a release agent with many advantages: no solvent in the system, environmentally friendly, wide range of peel force (1 ~ 1000g / inch), long-term stable peel force, low silicon transfer, little impact on the object, etc.

[0004] Solvent-free silicone release agents are generally composed of vinyl-containing polysiloxane, inhibitors, hydrogen-containing silicone oil, expandable porous microspheres and catalysts. Among them, the main component is vinyl-containing polysiloxane, which provides the vinyl functional groups required for the cross-linking reaction; the inhibitor is acetylenic alcohols, which can ensure that the release agent has a longer bath time at room temperature (20-40°C); the cross-linking agent is hydrogen-containing silicone oil, which provides the silicon-hydrogen functional groups required for the cross-linking reaction; the expandable porous microspheres are particles made of acrylic polymers, and after the surface is corona treated, they have the characteristics of lightness, porosity and foaming.

[0005] The holes on the surface of ordinary expanded microspheres are relatively sparse, and they cannot achieve the expansion and foaming effect after being heated and expanded, that is, they do not have a high specific surface area. In addition, the currently available expanded microspheres are mostly made of polyolefin materials such as PE and PP, which are easy to expand when heated and easy to collapse when subjected to force after cooling. Summary of the invention

[0006] One of the purposes of the present invention is to provide a solvent-free silicone release agent, which can form a layer of porous expanded microsphere structure on the surface after heat curing, with a sharp increase in specific surface area and a greatly reduced unit contact area with the adhered object, thereby reducing silicon transfer.

[0007] In order to achieve the above-mentioned object of the invention, the present invention adopts the following technical solutions:

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

[0009] 100 parts of vinyl-containing polysiloxane;

[0010] 0.005-0.05 parts of 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 to 5.0 parts of catalyst.

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

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

[0016] In one embodiment of the present invention, the inhibitor is an acetylene alcohol inhibitor, preferably one or more of ethynyl cyclohexanol, dimethyl hexynol, methyl butynol, and methyl acetylene alcohol.

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

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

[0019] In one embodiment of the present invention, the expandable porous microspheres are corona treated; preferably, the particle size range of the expandable porous microspheres is 5-150 μm, and the preferred particle size range is 10-70 μm; preferably, the true density range of the expandable porous microspheres is 0.05-1.00 g / cm3, and the preferred true density range is 0.10-0.70 g / cm3; preferably, the specific surface area of ​​the expandable porous microspheres is 5-70 m2 / g, and the preferred specific surface area is 10-50 m2 / g.

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

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

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

[0023] P1: corona treated expandable porous microspheres;

[0024] P2: Vinyl-containing polysiloxane, inhibitor, hydrogen-containing silicone oil and corona-treated expandable porous microspheres are mixed, a catalyst is added, and the mixture is stirred to obtain a release agent.

[0025] In one embodiment of the present invention, the corona treatment in P1 adopts plasma corona treatment; preferably, the parameters of the corona treatment are power 500-800W, flame temperature 40-50°C, input standard pressure 0.4-0.5MPa, and corona time 10-15min.

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

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

[0028] (2) The specific surface area of ​​the expanded microspheres after corona treatment is greatly increased, and better silicon transfer effect can be obtained when used in release agents;

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

[0030] The technical solution of the present invention will be described below in conjunction with specific examples. The examples used are only used to explain the present invention and are not used to limit the scope of the present invention.

[0031] Raw materials and sources:

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

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

[0034] Inhibitor, ethynylcyclohexanol, Aladdin, analytical grade;

[0035] Inhibitor, methylbutynol, Aladdin, analytical grade;

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

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

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

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

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

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

[0042] Expandable porous microspheres: acrylic material, Expancel920MB120, particle size 120-150μm, vacuum degree 0.5-0.7g / cm 3 , with a specific surface area of ​​30-50m 2 / g, Nouryon, industrial products;

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

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

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

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

[0047] Aging conditions: Aging in an oven at 70°C 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. The expanded microspheres 120DU25 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 120DU25 after corona treatment are recorded as S3.

[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 after corona treatment are denoted as Expancel 920 MB 120 and denoted 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] Add 100g vinyl-containing polysiloxane, HS-350, 0.010g dimethyl acetylene alcohol, 2.6g hydrogen-containing silicone oil, RH-H510, and 2.0g expandable porous microspheres S1 into a glass cup and stir for 30min; slowly add 1.0g platinum catalyst, HSL 5000 dropwise into the above mixture and stir for 20min to finally obtain the required release agent.

[0062] Example 2

[0063] Add 100g vinyl-containing polysiloxane, HS-220, 0.030g methyl butynol, 2.2g hydrogen-containing silicone oil, RH-H516, and 2.0g expandable porous microspheres S2 into a glass cup and stir for 30min; slowly add 4.0g platinum catalyst, HSL 3000 dropwise into the above mixture and stir for 20min to finally obtain the required release agent.

[0064] Example 3

[0065] Add 100g vinyl-containing polysiloxane, HS-350, 0.020g dimethyl acetylene alcohol, 2.6g hydrogen-containing silicone oil, RH-H510, and 2.0g expandable porous microspheres S3 into a glass cup and stir for 30min; slowly add 1.5g platinum catalyst, HLS 5000 dropwise into the above mixture and stir for 20min to finally obtain the required release agent.

[0066] Example 4

[0067] Add 100g vinyl-containing polysiloxane, HS-350, 0.020g dimethyl acetylene alcohol, 2.6g hydrogen-containing silicone oil, RH-H510, and 1.0g expandable porous microspheres S3 into a glass cup and stir for 30min; slowly add 1.5g platinum catalyst, HLS 5000 dropwise into the above mixture and stir for 20min to finally obtain the required release agent.

[0068] Example 5

[0069] Add 100g vinyl-containing polysiloxane, HS-350, 0.020g dimethyl acetylene alcohol, 2.6g hydrogen-containing silicone oil, RH-H510, and 4.0g expandable porous microspheres S3 into a glass cup and stir for 30min; slowly add 1.5g platinum catalyst, HLS 5000 dropwise into the above mixture and stir for 20min to finally obtain the required release agent.

[0070] Example 6

[0071] Add 100g vinyl-containing polysiloxane, HS-350, 0.020g dimethyl acetylene alcohol, 2.6g hydrogen-containing silicone oil, RH-H510, and 2.0g expandable porous microspheres S4 into a glass cup and stir for 30 minutes; slowly add 1.5g platinum catalyst, HLS 5000 dropwise into the above mixture and stir for 20 minutes to finally obtain the required release agent.

[0072] Example 7

[0073] Add 100g vinyl-containing polysiloxane, HS-350, 0.020g dimethyl acetylene alcohol, 2.6g hydrogen-containing silicone oil, RH-H510, and 2.0g expandable porous microspheres S5 into a glass cup and stir for 30min; slowly add 1.5g platinum catalyst, HLS 5000 dropwise into the above mixture and stir for 20min to finally obtain the required release agent.

[0074] Example 8

[0075] Add 100g vinyl-containing polysiloxane, HS-350, 0.020g dimethyl acetylene alcohol, 2.6g hydrogen-containing silicone oil, RH-H510, and 2.0g expandable porous microspheres S6 into a glass cup and stir for 30 minutes; slowly add 1.5g platinum catalyst, HLS 5000 dropwise into the above mixture and stir for 20 minutes to finally obtain the required release agent.

[0076] Comparative Example 1

[0077] Compared with Example 3, the difference is that the expandable porous microspheres are not subjected to plasma corona treatment.

[0078] Add 100g vinyl-containing polysiloxane, HS-350, 0.020g dimethyl acetylene alcohol, 2.6g hydrogen-containing silicone oil, RH-H510, 2.0g expandable porous microspheres, 120DU25, no corona treatment into a glass cup, and stir for 30min; slowly add 1.5g platinum catalyst, HLS 5000 dropwise into the above mixture, stir for 20min, and finally obtain the required release agent.

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

[0080]

[0081] It can be seen from Examples 1, 2 and 3 that the residual adhesion and aging peeling force of the release agent coating prepared from the raw materials within the parameter range of the patent claims are equivalent, and the parameter range of the raw materials is all effective range;

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

[0083] It can be seen from Examples 3 and 6 and 7 that the expandable microspheres after corona treatment within the parameter range of the patent claims can obtain excellent residual adhesion and aging peeling performance;

[0084] It can be seen from Examples 3 and 8 that the expandable microspheres made of acrylic acid and the expandable microspheres made of polystyrene have comparable residual adhesion and aging peeling performance;

[0085] It can be seen from Example 3 and Comparative Example 1 that, compared with the expandable microspheres that have not been corona treated, the residual adhesion and aging peeling force of the expandable porous microspheres that have been corona treated are significantly improved.

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

[0087] Those skilled in the art will appreciate that, based on the teachings of this specification, some modifications or adjustments may be made to the present invention, and these modifications or adjustments should also be within the scope defined by the claims of the present invention.

Claims

1. A solvent-free silicone release agent, characterized in that: The release agent is prepared from raw materials containing the following mass ratios: 100 parts of vinyl-containing polysiloxane; 0.005-0.05 parts of inhibitor; 0.5-5.0 parts of hydrogen-containing silicone oil; 0.5-10.0 parts of expandable porous microspheres; 1.0 to 5.0 parts of catalyst.

2. The release agent according to claim 1, characterized in that The mass percentage of vinyl in the ethylene-containing polysiloxane is 0.1% to 2.0%, preferably 0.3% to 1.2%.

3. The release agent according to claim 1 or 2, characterized in that: The inhibitor is an acetylene alcohol inhibitor, preferably one or more of ethynyl cyclohexanol, dimethyl hexynol, methyl butynol, and methyl acetylene alcohol.

4. The release agent according to any one of claims 1 to 3, characterized in that The hydrogen content in the hydrogen-containing silicone oil is 0.6-2.0 wt %, and preferably 1.0-1.6 wt %.

5. The release agent according to any one of claims 1 to 4, characterized in that The expandable porous microspheres are microparticles made of polymer, preferably microparticles made of acrylic acid; and / or, the expandable porous microspheres are corona treated; Preferably, the expandable porous microspheres have a particle size range of 5-150 μm, preferably a particle size range of 10-70 μm; Preferably, the true density of the expandable porous microspheres is in the range of 0.05-1.00 g / cm 3 The preferred true density range is 0.10-0.70 g / cm 3 ; Preferably, the specific surface area of ​​the expandable porous microspheres is 5-70 m 2 / g The preferred specific surface area is 10-50m 2 / g.

6. The release agent according to any one of claims 1 to 5, characterized in that The catalyst is selected from metal catalysts, preferably platinum catalysts, and the platinum content thereof is 3000ppm to 10000ppm.

7. A method for preparing a solvent-free silicone release agent, the method for preparing the silicone release agent according to any one of claims 1 to 6, characterized in that: The method comprises the following steps: P1: corona treated expandable porous microspheres; P2: Vinyl-containing polysiloxane, inhibitor, hydrogen-containing silicone oil and corona-treated expandable porous microspheres are mixed, a catalyst is added, and the mixture is stirred to obtain a release agent.

8. The method according to claim 7, characterized in that In P1, the corona treatment adopts plasma corona treatment; Preferably, the parameters of the corona treatment are: power 500-800 W, flame temperature 40-50° C., input gauge pressure 0.4-0.5 MPa, and corona time 10-15 min.

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