Organic silicon pressure-sensitive adhesive composition and preparation method thereof

Abstract

The invention provides an organic silicon pressure-sensitive adhesive composition and a preparation method thereof. The organic silicon pressure-sensitive adhesive composition comprises organic silicon resin, organic silicon raw rubber, an organic solvent and an organic silicon end-capping reagent, the organic silicon resin is MQ resin, the MQ ratio range is 0.5-1.5, and the mass ratio of hydroxyl in the organic silicon MQ resin is 1.5-3.5%; the weight ratio of the organic silicon raw rubber to the organic silicon resin is 100: (85-265); the organic silicon raw rubber comprises alkyl alkenyl polydimethylsiloxane and hydroxyl polydimethylsiloxane, and the mass ratio of vinyl in the alkyl alkenyl polydimethylsiloxane is 0.1%; wherein the mass ratio of the alkyl alkenyl polydimethylsiloxane to the hydroxyl polydimethylsiloxane is less than or equal to 3: 4. Compared with the prior art, the organic silicon pressure-sensitive adhesive composition has excellent initial adhesion and stripping performance, and in addition, the production process is flexible and convenient.

Description

Technical Field

[0001] The invention belongs to the technical field of organosilicon pressure-sensitive adhesive composition products, and relates to an organosilicon pressure-sensitive adhesive composition with high initial adhesion and a preparation method thereof. Background Art

[0002] Pressure-sensitive adhesive is a pressure-sensitive adhesive that only requires slight pressure to bond during use. It does not require solvents, heating, light or other means. It is not easily damaged when peeled and will not dry up for a long time. It is widely used in the fields of automobiles, packaging, building materials, electronic appliances, daily necessities, and medical care, and plays a connecting role in bundling, sealing, insulation, protection, delivery and fixation.

[0003] Silicone pressure-sensitive adhesive compositions are usually divided into addition type and condensation type. The addition type has excellent peel force stability, coverage, and residual force, and can be used to compound tape substrates with poor heat resistance. It has a wide temperature range and a safe curing process, and is suitable for high-performance applications. The condensation type has higher bonding strength, good electrical properties, chemical resistance, moisture resistance, and weather resistance, and a wide temperature range. It can bond a variety of difficult-to-bond materials, such as untreated polyolefins, fluoroplastics, polyimides, and polycarbonates. In addition, it has the industrial advantages of low process cost, long material tank life, and high recycling rate. However, with the rapid development of electronic products, such as the development of new energy battery technology, the existing silicone pressure-sensitive adhesive composition products have become increasingly difficult to meet the corresponding industry needs in terms of initial adhesion, sustained adhesion, peel force, production process, and stability under long-term storage. Patent CN202110798040.5 discloses a silicone pressure-sensitive adhesive composition with good initial adhesion and peeling properties. However, due to the addition of BPO cross-linking agent, the product composition is not simple enough. In addition, it is difficult to apply to industries with higher requirements for initial adhesion.

[0004] Therefore, there is an urgent need for a silicone pressure-sensitive adhesive and a preparation method thereof, which can achieve excellent initial adhesion performance while maintaining good peeling performance. Summary of the invention

[0005] In view of the above-mentioned deficiencies in the prior art, the present invention provides:

[0006] A silicone pressure-sensitive adhesive composition, comprising silicone resin, silicone rubber, organic solvent, and silicone end-capping agent; the silicone resin is silicone MQ resin, the MQ ratio range is 0.5-1.5, and the mass proportion of hydroxyl in the silicone MQ resin is 1.5-3.5%; the weight ratio of the silicone rubber to the silicone resin is 100:85-265; the silicone rubber comprises alkylene polydimethylsiloxane and hydroxyl polydimethylsiloxane, and the mass proportion of vinyl in the alkylene polydimethylsiloxane is 0.1%; wherein:

[0007] The mass ratio of the alkene polydimethylsiloxane to the hydroxy polydimethylsiloxane is 2:3-3:4.

[0008] Furthermore, the mass ratio of the alkene polydimethylsiloxane to the hydroxy polydimethylsiloxane is 3:4.

[0009] Furthermore, the weight ratio of the organic silicone rubber to the organic silicone resin is 100:100-133.

[0010] Furthermore, the weight ratio of the organic silicone rubber to the organic silicone resin is 100:133.

[0011] Furthermore, the weight ratio of the organic silicon raw rubber to the organic silicon end-capping agent is 100:0.4-6.5.

[0012] Furthermore, the weight ratio of the organic silicone rubber to the organic solvent is 100:70-200.

[0013] Furthermore, the weight ratio of the organic silicone rubber to the organic solvent and the organic silicone capping agent is 100:104:2.1.

[0014] A method for producing the above-mentioned organosilicon pressure-sensitive adhesive composition comprises: S1. preparing an MQ resin solution, S2. preparing an organosilicon pressure-sensitive adhesive composition; wherein:

[0015] The S1. preparing the MQ resin solution comprises S11. mixing the raw materials of the silicone MQ resin, S12. heating to reflux, S13. extracting and filtering;

[0016] The S2. Preparation of the silicone pressure-sensitive adhesive composition comprises: S21. Mixing the silicone resin, the organic solvent, and the silicone rubber, S22. Adding the hydroxy silicone capping agent;

[0017] The steps of adjusting the viscosity of the organic silicone raw rubber are also included between S1. preparing the MQ resin solution and 2. preparing the organic silicone pressure-sensitive adhesive composition.

[0018] Compared with the prior art, the organic silicone pressure-sensitive adhesive and the preparation method thereof provided by the present invention have the following beneficial effects:

[0019] (1) Excellent initial adhesion without the need to add a crosslinking agent;

[0020] (2) Good high peeling performance;

[0021] (3) Flexible high initial viscosity adjustment process. DETAILED DESCRIPTION

[0022] The embodiment of the present invention provides an organic silicone pressure-sensitive adhesive composition, comprising an organic silicone resin, an organic silicone raw rubber, an organic solvent, and an organic silicone capping agent; the organic silicone resin is an organic silicone MQ resin, the MQ ratio range is 0.5-1.5, and the mass proportion of hydroxyl groups in the organic silicone MQ resin is 1.5-3.5%; the weight ratio of the organic silicone raw rubber to the organic silicone resin is 100:85-265; the organic silicone raw rubber comprises alkylene polydimethylsiloxane and hydroxyl polydimethylsiloxane, and the mass proportion of vinyl in the alkylene polydimethylsiloxane is 0.1%; wherein:

[0023] The mass ratio of the alkene polydimethylsiloxane to the hydroxy polydimethylsiloxane is 2:3-3:4.

[0024] The organic silicone pressure-sensitive adhesive of the embodiment of the present invention reduces auxiliary agents such as cross-linking agents while maintaining good initial adhesion and peeling properties. Compared with the existing silicone pressure-sensitive adhesive, the formula is simpler.

[0025] Furthermore, the mass ratio of the alkene polydimethylsiloxane to the hydroxy polydimethylsiloxane is 3:4.

[0026] Specifically, the M / Q value ranges from 0.4 to 1.2; preferably, the M / Q value is 0.75.

[0027] Specifically, the mass percentage of hydroxyl groups in the organic silicon MQ resin is 2.0%.

[0028] Furthermore, the weight ratio of the organic silicone rubber to the organic silicone resin is 100:100-133.

[0029] Furthermore, the weight ratio of the organic silicone rubber to the organic silicone resin is 100:133.

[0030] Furthermore, the weight ratio of the organic silicon raw rubber to the organic silicon end-capping agent is 100:0.4-6.5.

[0031] Furthermore, the weight ratio of the organic silicone rubber to the organic solvent is 100:70-200.

[0032] Furthermore, the weight ratio of the organic silicone rubber to the organic solvent and the organic silicone capping agent is 100:104:2.1.

[0033] Specifically, the organosilicon MQ resin is selected from the organosilicon MQ resin commonly used in the art and prepared from tetraethyl orthosilicate and hexamethyldisiloxane, and is prepared by hydrolyzing and condensing hexamethyldisiloxane as the M group and tetraethyl orthosilicate as the Q group.

[0034] More specifically, the weight ratio of ethyl orthosilicate to hexamethyldisiloxane in the organic silicon MQ resin is 100:20-60; preferably, the weight ratio is 100:30.

[0035] Specifically, the organosilicon capping agent is a hydroxyl organosilicon capping agent.

[0036] Specifically, the hydroxyl organic silicon end-capping agent is one or a combination of hydroxyl-terminated polydimethylsiloxane and hydroxyl-terminated trifluoropropylmethylpolysiloxane; preferably, hydroxyl-terminated polydimethylsiloxane. In this embodiment, the hydroxyl organic silicon end-capping agent is selected from 107 glue.

[0037] Specifically, the solvent is one of toluene and xylene. In this embodiment, the organic solvent is toluene.

[0038] The present invention provides a method for producing the above-mentioned organosilicon pressure-sensitive adhesive composition, comprising: S1. preparing an MQ resin solution, S2. preparing an organosilicon pressure-sensitive adhesive composition; wherein:

[0039] The S1. preparing the MQ resin solution comprises S11. mixing the raw materials of the silicone MQ resin, S12. heating to reflux, S13. extracting and filtering;

[0040] The S2. Preparation of the silicone pressure-sensitive adhesive composition comprises: S21. Mixing the silicone resin, the organic solvent, and the silicone rubber, S22. Adding the hydroxy silicone capping agent;

[0041] The steps of adjusting the viscosity of the organic silicone raw rubber are also included between S1. preparing the MQ resin solution and 2. preparing the organic silicone pressure-sensitive adhesive composition.

[0042] The method for preparing the silicone pressure-sensitive adhesive in the embodiment of the present invention can appropriately adjust the initial adhesion by adjusting the molecular weight of the silicone raw rubber based on the composition formula, which makes the production more flexible. In particular, when the composition ratio is abnormal during the production process, the molecular weight of the silicone raw rubber can be adjusted to achieve the purpose of obtaining qualified products, which can effectively reduce the defective product rate and thus improve production efficiency.

[0043] Specifically, the raw materials of the mixed silicone MQ resin in S11 include: measuring tetraethyl orthosilicate and hexamethyldisiloxane, adding a mixed solution of ethanol and hydrochloric acid containing a catalyst after stirring, and then adding deionized water; optionally, in the mixed solution of ethanol and hydrochloric acid, the mass of ethanol accounts for 5%-10% of the total feed mass, and the mass of hydrochloric acid accounts for 1%-3% of the total feed mass.

[0044] Specifically, the S12. heating to reflux includes: heating to the reflux temperature for reflux reaction; optionally, the reflux reaction time is 2-6h.

[0045] Specifically, the S13. extraction and filtration comprises: adding toluene and standing to separate the layers, then pouring out the resin layer and distilling it until the resin solution is neutral, and filtering to obtain the MQ resin solution.

[0046] Specifically, the S21. mixing the silicone resin, organic solvent and silicone rubber comprises: adding the silicone resin, organic solvent and silicone rubber in a specified weight and order, and controlling the temperature to stir and mix them evenly.

[0047] The present invention provides Examples 1-6, Comparative Examples 1-5 and test results as shown in Table 1-2 below. In the Examples and Comparative Examples, the rolling ball and peeling properties of the composition were tested with M / Q, resin / raw rubber weight ratio, and alkylene polydimethylsiloxane / hydroxy polydimethylsiloxane weight ratio as variables:

[0048] Example 1

[0049] S1. Add about 200 parts of tetraethyl orthosilicate and 60 parts of hexamethyldisiloxane (M / Q value 0.75) into the container, stir for 10 minutes, then add a mixture of ethanol and hydrochloric acid (the mass of ethanol accounts for 7.5% of the total feed mass, and the mass of hydrochloric acid accounts for 2% of the total feed mass), and then immediately add 60g of deionized water to the flask, and control the addition to be completed within 1 hour; heat to reflux temperature and maintain reflux reaction for 4 hours; add 120 parts of toluene to extract for 1 hour, pour into a separating funnel and let stand for stratification; pour the resin layer into a four-necked flask, distill until the resin solution is neutral, and filter to obtain the desired MQ resin solution;

[0050] S2. Adjust the viscosity of the silicone rubber;

[0051] S3. Add 320 parts of silicone resin, 250 parts of organic solvent and 240 parts of silicone rubber according to the specified weight and order, control the temperature and stir to mix evenly; then, add 5 parts of the hydroxyl end-capping agent to obtain the high initial viscosity silicone pressure-sensitive adhesive.

[0052] Embodiment 2-4

[0053] The difference between Example 2-4 and Example 1 is that the ratio of M to Q in the silicone resin is different.

[0054] Embodiment 5-6

[0055] The difference between Example 5-6 and Example 1 is that the ratio of the organic silicone resin to the organic silicone rubber is different.

[0056] Comparative Example 1-2

[0057] The difference between Comparative Example 1-2 and Example 1 is the mass ratio of alkylene polydimethylsiloxane to hydroxy polydimethylsiloxane in the silicone rubber.

[0058] Comparative Examples 3-4

[0059] The difference between Comparative Example 3-4 and Example 1 is that the ratio of the organic silicone resin to the organic silicone raw rubber is different.

[0060] Comparative Example 5

[0061] The difference between Example 1 and Comparative Example 5 is that the molecular weights of the organic silicone rubber are different.

[0062] Examples 1-6 and Comparative Examples 1-5 are shown in Table 1:

[0063] Table 1

[0064]

[0065] The test items and methods of Examples 1-6 and Comparative Examples 1-5 are as follows:

[0066] (1) Peel strength: Determined according to method 1 of GB / T 2792-2014 "Test method for peel strength of adhesive tape". Specifically, the adhesive solution was coated on a 50±2μm PET film with a thickness of 15±2μm, first cured at 110°C for 3 min, then placed in a 50°C oven for further aging for 48 h, and then tested;

[0067] (2) Initial adhesion: Determined by the inclined rolling ball method in accordance with Method A of GB / T 4852-2002 “Test method for initial adhesion of pressure-sensitive adhesive tapes (rolling ball method)”.

[0068] The test results are shown in Table 2 below:

[0069] Table 2

[0070]

[0071] According to Table 1-2 above:

[0072] (1) Examples 1-4 have different ratios of M to Q; the test results show that without adding a cross-linking agent, the initial adhesion ball is as small as 21# and as large as 30#, showing excellent initial adhesion performance.

[0073] (2) The mass ratios of alkylene polydimethylsiloxane to hydroxy polydimethylsiloxane in Example 1 and Comparative Examples 1-2 are different; the test results show that the ratios of Example 1 and Comparative Example 4 both exhibit good initial adhesion performance, while the initial adhesion performance of Example 5 is poor. Therefore, when the mass ratio of alkylene polydimethylsiloxane to hydroxy polydimethylsiloxane is ≥3:4, the initial adhesion becomes poor, and when the mass ratio is between 2:3 and 3:4, it is easy to obtain high initial adhesion; in addition, when the mass ratio is 2:3, the peeling becomes poor, and the peeling force of high-viscosity pressure-sensitive adhesives is generally not less than 750 gf. Therefore, when the mass ratio is 3:4, the pressure-sensitive adhesive of the present invention simultaneously obtains excellent initial adhesion and peeling performance.

[0074] (3) The ratio of the silicone resin to the silicone rubber in Examples 1, 5-6 and Comparative Examples 3-4 is different, wherein the ratio of the silicone resin to the silicone rubber in Comparative Example 1 is 2.67, which exceeds the weight range of 85-265 of the silicone resin of the present invention, and the ratio of the silicone rubber to the silicone resin in Comparative Example 2 is 0.67, which is less than the weight range of 85-265; the test results show that when the weight ratio of the silicone rubber to the silicone resin is 100:85-265, the peeling and initial adhesion can simultaneously present good performance, while when it exceeds this range, the initial adhesion performance will suddenly deteriorate, and when it is less than this range, the peeling performance will suddenly deteriorate. Therefore, when the weight ratio is at least greater than 100:265 and less than 100:85, the pressure-sensitive adhesive of the present invention will likely obtain good initial adhesion and peeling performance, and when the weight ratio is further less than 100:133, the performance is even better, and it is very suitable for high peeling force and high initial adhesion pressure-sensitive adhesive products.

[0075] (4) The molecular weights of the silicone raw rubber in Example 1 and Comparative Example 5 are different, and Comparative Example 3 significantly reduces the molecular weight of the silicone raw rubber. The test results show that reducing the molecular weight of the silicone raw rubber is beneficial to the initial adhesion. In some products that do not require high peeling force, the initial adhesion performance can be increased or decreased by adjusting the molecular weight of the silicone raw rubber to obtain a product that meets the requirements, which makes production more flexible.

[0076] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit the protection scope of the present invention. Those skilled in the art should understand that the technical solution of the present invention can be deduced or replaced by equivalents without departing from the essence and scope of the technical solution of the present invention.

Claims

1. A silicone pressure-sensitive adhesive composition, comprising a silicone resin, a silicone rubber, an organic solvent, and a silicone end-capping agent; the silicone resin is a silicone MQ resin, the MQ ratio range is 0.5-1.5, and the mass proportion of hydroxyl groups in the silicone MQ resin is 1.5-3.5%; the weight ratio of the silicone rubber to the silicone resin is 100:85-265; the silicone rubber comprises alkylene polydimethylsiloxane and hydroxyl polydimethylsiloxane, and the mass proportion of vinyl groups in the alkylene polydimethylsiloxane is 0.1%; characterized in that: The mass ratio of the alkene polydimethylsiloxane to the hydroxy polydimethylsiloxane is 2:3-3:

4.

2. The organosilicon pressure-sensitive adhesive composition according to claim 1, characterized in that: The mass ratio of the alkylene polydimethylsiloxane to the hydroxy polydimethylsiloxane is 3:

4.

3. The organosilicon pressure-sensitive adhesive composition according to claim 1, characterized in that: The weight ratio of the organic silicon raw rubber to the organic silicon resin is 100:100-133.

4. The organosilicon pressure-sensitive adhesive composition according to claim 3, characterized in that: The weight ratio of the organic silicon raw rubber to the organic silicon resin is 100:

133.

5. The organosilicon pressure-sensitive adhesive composition according to claim 1, characterized in that: The weight ratio of the organic silicon raw rubber to the organic silicon end-capping agent is 100:0.4-6.

5.

6. The organosilicon pressure-sensitive adhesive composition according to claim 5, characterized in that: The weight ratio of the organic silicon raw rubber to the organic solvent is 100:70-200.

7. The organosilicon pressure-sensitive adhesive composition according to claim 6, characterized in that: The weight ratio of the organic silicon raw rubber to the organic solvent and the organic silicon end-capping agent is 100:104:2.

1.

8. A method for producing the organosilicon pressure-sensitive adhesive composition according to claim 1, comprising: S1. Preparing MQ resin solution, S2. Preparing silicone pressure-sensitive adhesive composition; characterized in that: The S1. preparing the MQ resin solution comprises S11. mixing the raw materials of the silicone MQ resin, S12. heating to reflux, S13. extracting and filtering; The S2. Preparation of the silicone pressure-sensitive adhesive composition comprises: S21. Mixing the silicone resin, the organic solvent, and the silicone rubber, S22. Adding the hydroxy silicone capping agent; The steps of adjusting the viscosity of the organic silicone raw rubber are also included between S1. preparing the MQ resin solution and 2. preparing the organic silicone pressure-sensitive adhesive composition.

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