Transparent dealcoholized silicone rubber with wide adhesion, low modulus and high elasticity and preparation method thereof

Abstract

The invention relates to the field of organosilicon sealants, and discloses a wide-adhesion, low-modulus, high-elasticity and transparent dealcoholized silicone rubber and a preparation method thereof.The wide-adhesion, low-modulus, high-elasticity and transparent dealcoholized silicone rubber is prepared from, by mass, 40-70 parts of methyl-terminated diethoxy polydimethylsiloxane, 30-60 parts of flexible polymer, 30-60 parts of modified white carbon black base material and 1-5 parts of silane cross-linking agent, 0.5-3 parts of a silane coupling agent and 0.2-1 part of a catalyst. The transparent dealcoholized silicone rubber prepared by the technical scheme has the advantages that the adhesive strength is obviously improved, the mechanical property is excellent, and the low-modulus and high-elasticity displacement capability requirements are met.

Description

Technical Field

[0001] The invention relates to the field of organic silicon sealants, and in particular to a transparent dealcoholized silicone rubber with wide adhesion, low modulus and high elasticity, and a preparation method thereof. Background Art

[0002] With the increasing awareness of environmental protection and consumers' pursuit of aesthetics and non-toxicity, in the field of silicone sealants, transparent dealcoholized silicone rubber has gradually emerged in the furniture and home improvement market due to its low odor, environmental protection, non-corrosiveness and excellent aesthetics. This material can not only meet the requirements of modern home decoration for cleanliness and safety, but also add a crystal clear artistic sense to the home environment. However, although transparent dealcoholized silicone rubber has many advantages, its limitations in practical applications cannot be ignored, especially the lack of extensive bonding and elasticity, which limits its wider application range. The above performance defects are mainly because the extensive bonding of silicone rubber prepared by acidic fillers is not as good as that of alkaline fillers such as calcium carbonate. In addition, the hydroxyl groups on silica consume part of the coupling agent, further weakening the bonding performance. Secondly, the hydroxyl groups on silica react with crosslinking agents / coupling agents to increase the crosslinking density of silicone rubber, resulting in poor elasticity and insufficient displacement capacity of transparent alcohol-type rubber. These problems make most of the transparent dealcoholized silicone rubbers on the market only suitable for easy-to-bond substrates such as bathroom glass products, tiles, and wood, but cannot provide reliable bonding effects for aluminum profiles, PMMA, and other materials commonly used in furniture and home decoration. In addition, this type of silicone rubber is not suitable for use in locations such as doors and windows that need to withstand large displacements and deformations, which greatly limits its application scenarios and development potential.

[0003] Chinese patent CN104004357A discloses a transparent dealcoholized one-component silicone rubber, which uses a capped 107 system to obtain a transparent dealcoholized silicone rubber with good storage stability and mechanical strength; Chinese patent CN103361023A discloses a transparent dealcoholized silicone rubber, which has good anti-yellowing performance through formula optimization; Chinese patent CN104829642A discloses a transparent dealcoholized silicone rubber, which improves its adhesion to aluminum, copper, and PC by using a specific silane coupling agent; Chinese patent CN109354875A discloses a transparent dealcoholized silicone rubber, which solves the "viscosity peak" and "structural problems" by using alkoxy-capped polydimethylsiloxane as a base polymer and treating white carbon black. However, the above patented technologies mainly focus on the improvement of storage stability, yellowing resistance, curing speed and specific substrate bonding, and do not have a volume on how to improve the extensive bonding of transparent dealcoholized silicone rubber and the displacement capacity of high elasticity and low modulus. Summary of the invention

[0004] The present invention aims to provide a transparent dealcoholized silicone rubber with wide adhesion, low modulus and high elasticity and a preparation method thereof, so as to solve the problems in the prior art that the transparent dealcoholized silicone rubber has insufficient extensive adhesion to the substrate and is difficult to meet the displacement capacity requirements of low modulus and high elasticity.

[0005] To achieve the above-mentioned purpose, the present invention adopts the following technical scheme: a widely adhesive, low-modulus, highly elastic transparent dealcoholized silicone rubber, which comprises, by weight, 40 to 70 parts of terminal methyl diethoxy polydimethylsiloxane, 30 to 60 parts of flexible polymer, 30 to 60 parts of modified white carbon black base material, 1 to 5 parts of silane crosslinking agent, 0.5 to 3 parts of silane coupling agent, and 0.2 to 1 part of catalyst.

[0006] Preferably, as an improvement, the viscosity of the methyl-terminated diethoxy polydimethylsiloxane is 10,000 to 80,000 mPa·s, and the structure is shown in formula (I):

[0007]

[0008] Preferably, as an improvement, the flexible polymer structure is as shown in formula (II):

[0009]

[0010] Wherein m is an integer of 600 to 1500, R1 and R2 are one of hydrogen, methyl, ethyl, n-propyl, n-butyl, isopropyl, isobutyl, phenyl and benzyl, and R1 and R2 are the same or different.

[0011] Preferably, as an improvement, the preparation method of the modified white carbon black base material is:

[0012] S1. Add dimethyl silicone oil into a kneader, add 50% of the total mass of dimethyl silicone oil, 5% to 15% of the total mass of dimethyl silicone oil, and 2% of the total mass of dimethyl silicone oil in batches. Deionized water, knead and stir evenly;

[0013] S2, heating and kneading;

[0014] S3. Under vacuum conditions, continue to heat up, knead and degas to obtain a modified silica base material.

[0015] Preferably, as an improvement, in step S1, the viscosity of the dimethyl silicone oil is 50 mPa·s to 2000 mPa·s, and the modifier is one or both of 1,3-bisaminomethyl-1,1,3,3-tetramethyldisiloxane and 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane.

[0016] Preferably, as an improvement, the silane crosslinking agent is at least one of methyltriethoxysilane, vinyltriethoxysilane, propyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, and n-dodecyltriethoxysilane.

[0017] Preferably, as an improvement, the silane coupling agent is at least one of γ-aminopropyltriethoxysilane, N-β-(aminoethyl)-γaminopropylmethyldimethoxysilane, N-β-(aminoethyl)-γaminopropylmethyldiethoxysilane, and N-(β-aminoethyl)-γ-aminopropyltriethoxysilane.

[0018] Preferably, as an improvement, the catalyst is an organic tin catalyst, and specifically at least one of dibutyltin dilaurate, dioctyltin dilaurate, dibutyltin dicaprate and dibutyltin bis(acetylacetonate) can be selected.

[0019] Preferably, as an improvement, a method for preparing a wide-adhesion, low-modulus, high-elastic transparent dealcoholized silicone rubber comprises the following steps:

[0020] Step 1: adding methyl-terminated diethoxy polydimethylsiloxane, a flexible polymer and a modified white carbon black base material into a high-speed disperser, and vacuuming and stirring to obtain a system I;

[0021] Step 2: adding a silane crosslinking agent and a silane coupling agent into system I, vacuuming and stirring to obtain system II;

[0022] Step 3: Add the catalyst into system II, evacuate and stir to obtain a widely-adhesive, low-modulus, highly elastic, transparent dealcoholized silicone rubber.

[0023] The principle and advantage of this solution are: in practical application, in this technical solution, the formula and preparation process of silicone rubber are upgraded as a whole to address the problems of insufficient extensive bonding of traditional white carbon black reinforced transparent dealcoholized silicone rubber in the prior art and the difficulty of existing transparent dealcoholized silicone rubber in taking into account both smooth construction performance and low modulus and high elasticity: by using a flexible polymer with high activity methoxy end-capping, it produces an activity difference with terminal methyl diethoxy polydimethylsiloxane and a crosslinking agent. During the curing process, the flexible polymer first reacts in situ to generate linear macromolecules, and then a crosslinking reaction occurs. It can avoid the problems of high colloid viscosity, inability to disperse evenly, and inability to smoothly apply glue caused by directly using an overly high molecular weight polymer to make glue, and can effectively increase the elongation of silicone rubber and reduce the modulus. In the technical research and development stage, the treatment method of white carbon black, the selection of flexible polymers, and the selection of crosslinking agents and coupling agents are the research and development difficulties of this technical solution. When this technical solution performs surface modification on white carbon black, amino-containing silyl ether is used as a modifier, which can not only reduce the hydroxyl content on the surface of white carbon black, but also use the alkalinity of amino groups to change white carbon black from an acidic filler to an alkaline filler, thereby improving the extensive adhesion of dealcoholized silicone rubber to the substrate. In addition, combined with a highly active methoxy-terminated flexible polymer, the adhesive strength of the transparent dealcoholized silicone rubber prepared by this technical solution is significantly improved, and the mechanical properties are excellent, meeting the displacement capacity requirements of low modulus and high elasticity. DETAILED DESCRIPTION

[0024] The following is further described in detail through specific implementations, but the implementation of the present invention is not limited thereto. Unless otherwise specified, the technical means used in the following implementations are conventional means well known to those skilled in the art; the experimental methods used are all conventional methods; the materials, reagents, etc. used can all be obtained from commercial channels.

[0025] A widely-adhesive, low-modulus, high-elastic transparent dealcoholized silicone rubber comprises, by weight, 40 to 70 parts of methyl-terminated diethoxy polydimethylsiloxane, 30 to 60 parts of flexible polymer, 30 to 60 parts of modified white carbon black base material, 1 to 5 parts of silane crosslinking agent, 0.5 to 3 parts of silane coupling agent, and 0.2 to 1 part of catalyst.

[0026] Among them, the viscosity of the terminal methyl diethoxy polydimethylsiloxane is 10,000 to 80,000 mPa·s, and the structure is shown in formula (I):

[0027]

[0028] The structure of the flexible polymer is shown in formula (II):

[0029]

[0030] Wherein m is an integer of 600 to 1500, R1 and R2 are selected from one of hydrogen, methyl, ethyl, n-propyl, n-butyl, isopropyl, isobutyl, phenyl and benzyl, and R1 and R2 are the same or different.

[0031] The preparation method of the modified white carbon black base material is:

[0032] S1. Add dimethyl silicone oil into a kneader, add 50% of white carbon black by weight of the dimethyl silicone oil, 5% to 15% of the total weight of the dimethyl silicone oil, and 2% of deionized water by weight of the dimethyl silicone oil in batches, and knead and stir evenly; wherein the viscosity of the dimethyl silicone oil is 50 mPa·s to 2000 mPa·s, and the modifier is one or a combination of 1,3-bisaminomethyl-1,1,3,3-tetramethyldisiloxane (AM-PDMS) and 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane (PM-PDMS);

[0033] S2, heat to 80℃ and knead for 5h

[0034] S3. Under vacuum conditions, the temperature is raised to 130°C, and the mixture is kneaded and degassed for 3 hours to obtain a modified silica base material.

[0035] The silane crosslinking agent is at least one of methyltriethoxysilane, vinyltriethoxysilane, propyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane and n-dodecyltriethoxysilane.

[0036] The silane coupling agent is at least one of γ-aminopropyltriethoxysilane, N-β-(aminoethyl)-γaminopropylmethyldimethoxysilane, N-β-(aminoethyl)-γaminopropylmethyldiethoxysilane, and N-(β-aminoethyl)-γ-aminopropyltriethoxysilane.

[0037] The catalyst is an organic tin catalyst, and specifically at least one of dibutyltin dilaurate, dioctyltin dilaurate, dibutyltin dicaprate and dibutyltin bis(acetylacetonate) can be selected.

[0038] A method for preparing a transparent dealcoholized silicone rubber with wide adhesion, low modulus and high elasticity, comprising the following steps:

[0039] Step 1: Add 40 to 70 parts of methyl-terminated diethoxy polydimethylsiloxane, 30 to 60 parts of flexible polymer and 30 to 60 parts of modified white carbon black base material into a high-speed disperser, and stir under vacuum for 10 minutes to obtain system I;

[0040] Step 2: Add 1 to 5 parts of silane crosslinking agent and 0.5 to 3 parts of silane coupling agent into system I, and stir under vacuum for 10 minutes to obtain system II;

[0041] Step 3: Add 0.2-1 parts of catalyst into system II, evacuate and stir for 20 minutes to obtain a transparent dealcoholized silicone rubber with wide adhesion, low modulus and high elasticity.

[0042] Example

[0043] Examples 1 to 6 are examples of the present invention. The difference between the examples lies in the difference in components and addition amounts. See Table 1 for details.

[0044] Table 1

[0045]

[0046] Taking Example 1 as an example, a method for preparing a wide-adhesion, low-modulus, high-elastic transparent dealcoholized silicone rubber is described in detail, comprising the following steps:

[0047] Step 1: Add 70 parts of terminal methyl diethoxy polydimethylsiloxane, 30 parts of flexible polymer and 30 parts of modified white carbon black base material into a high-speed disperser, and stir under vacuum for 10 minutes to obtain system I;

[0048] Step 2: Add 1 part of silane crosslinking agent and 3 parts of silane coupling agent into system I, vacuum and stir for 10 minutes to obtain system II;

[0049] Step 3: Add 0.2 parts of catalyst into system II, evacuate and stir for 20 minutes to obtain a transparent dealcoholized silicone rubber with wide adhesion, low modulus and high elasticity.

[0050] Comparative Example 1

[0051] The difference between Comparative Example 1 and Example 3 is that in this comparative example, the flexible polymer is replaced by an equal mass of methyldiethoxypolydimethylsiloxane (viscosity 80000 mPa·s).

[0052] Comparative Example 2

[0053] The difference between Comparative Example 2 and Example 3 is that in this comparative example, the flexible polymer is replaced by an equal mass of methylvinylmethoxypolydimethylsiloxane, and the structural formula is as shown in Formula (III).

[0054]

[0055] Comparative Example 3

[0056] The difference between Comparative Example 3 and Example 3 is that in this comparative example, the silane crosslinking agent is replaced by methyltrimethoxysilane of equal mass.

[0057] Comparative Example 4

[0058] The difference between Comparative Example 4 and Example 3 is that in this comparative example, the silane coupling agent is replaced by equal masses of γ-aminopropyltrimethoxysilane and N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane (each accounting for 50%).

[0059] Comparative Example 5

[0060] The difference between this comparative example and Example 3 is that in this comparative example, the white carbon black modifiers AM-PDMS and PM-PDMS are replaced by an equal mass of hexamethyldisilazane.

[0061] Comparative Example 6

[0062] The difference between this comparative example and Example 3 is that in this comparative example, no white carbon black modifier is added.

[0063] Experimental Example Performance Test

[0064] The following performance tests were conducted on the polyurethane synthetic leather after the wide-adhesion, low-modulus, high-elasticity transparent dealcoholized silicone rubber prepared in the above embodiments and comparative examples was surface treated with the water-based organic silicone coating material for leather. The test indicators and test methods are shown in Table 2 below:

[0065] Table 2

[0066] Serial number Test indicators Test Method 1 Shear Strength GB / T 7124-2008 "Test for tensile shear strength of adhesives (rigid material to rigid material)" 2 Tensile bond strength GB / T 13477.8-2017 Test methods for building sealing materials Part 8: Determination of tensile adhesion 3 Elongation at break GB / T 13477.8-2017 Test methods for building sealing materials Part 8: Determination of tensile adhesion 4 100% tensile modulus GB / T 13477.8-2017 Test methods for building sealing materials Part 8: Determination of tensile adhesion 5 100% stretch bond GB / T 13477.10-2017 Test methods for building sealing materials Part 10: Determination of fixed-tension adhesion

[0067] The test results are shown in Table 3: In Comparative Example 1, the flexible polymer is not replaced with an equal mass of methyldiethoxypolydimethylsiloxane, and linear macromolecules cannot be generated in situ, the silicone rubber elongation is low, the 100% tensile modulus is high, and the 100% fixed stretch adhesive colloid is cracked; in Comparative Example 2, the flexible polymer is replaced with an equal mass of methylvinylmethoxypolydimethylsiloxane, the reaction activity of methylvinylmethoxypolydimethylsiloxane is low, the in situ generation of linear macromolecules cannot be achieved, and the cross-linking reaction is incomplete, resulting in a decrease in the strength of the silicone rubber, a decrease in elongation, a high 100% tensile modulus, and a cracking of the 100% fixed stretch adhesive colloid; in Comparative Example 3, the low-activity silane crosslinker is replaced with an equal mass of higher-activity methyltrimethoxysilane, and methyltrimethoxysilane is replaced with an equal mass of methyltrimethoxysilane. The alkane competes with the flexible polymer to react, affecting the in-situ generation of linear macromolecules, the silicone rubber has a low elongation, a high 100% tensile modulus, and the 100% fixed-stretch adhesive colloid is cracked; in Comparative Example 4, the less active ethoxysilane coupling agent is replaced by a methoxysilane coupling agent, and the methoxysilane coupling agent competes with the flexible polymer to react, affecting the in-situ generation of linear macromolecules, the silicone rubber has a low elongation, a high 100% tensile modulus, and the 100% fixed-stretch adhesive colloid is cracked; in Comparative Example 5, the white carbon black modifiers AM-PDMS and PM-PDMS are replaced with hexamethyldisilazane of equal mass, although the hydroxyl groups on the surface of the white carbon black can also be reduced, the white carbon black cannot be modified to alkaline, so the silicone rubber has poor extensive bonding, and the shear strength of most substrates is low. In Comparative Example 6, the white carbon black is not modified, and the hydroxyl groups on the surface of the white carbon black are more and acidic, so the silicone rubber has poor extensive bonding, the shear strength of most substrates is low, and the elongation is also slightly reduced. By adopting the schemes of Examples 1 to 6, transparent dealcoholized silicone rubber with good performance can be prepared.

[0068] Table 3

[0069]

[0070]

[0071] The above is only an embodiment of the present invention, and the common knowledge such as the known specific technical solutions and / or characteristics in the solution is not described in detail here. It should be pointed out that for those skilled in the art, without departing from the technical solution of the present invention, several modifications and improvements can be made, which should also be regarded as the protection scope of the present invention, and these will not affect the effect of the implementation of the present invention and the practicality of the patent. The scope of protection required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the specification can be used to interpret the content of the claims.

Claims

1. A wide-adhesion, low-modulus, high-elastic transparent dealcoholized silicone rubber, characterized by: The invention comprises, by weight, 40 to 70 parts of terminal methyl diethoxy polydimethylsiloxane, 30 to 60 parts of flexible polymer, 30 to 60 parts of modified white carbon black base material, 1 to 5 parts of silane crosslinking agent, 0.5 to 3 parts of silane coupling agent and 0.2 to 1 part of catalyst.

2. The wide-adhesion, low-modulus, high-elastic transparent dealcoholized silicone rubber according to claim 1, characterized in that: The viscosity of the methyl-terminated diethoxy polydimethylsiloxane is 10,000 to 80,000 mPa·s, and the structure is shown in formula (I):

3. The wide-adhesion, low-modulus, high-elastic transparent dealcoholized silicone rubber according to claim 2, characterized in that: The flexible polymer structure is shown in formula (II): Wherein m is an integer of 600 to 1500, R1 and R2 are one of hydrogen, methyl, ethyl, n-propyl, n-butyl, isopropyl, isobutyl, phenyl and benzyl, and R1 and R2 are the same or different.

4. The wide-adhesion, low-modulus, high-elastic transparent dealcoholized silicone rubber according to claim 3, characterized in that: The preparation method of the modified white carbon black base material is: S1. Add dimethyl silicone oil into a kneader, add 50% of the total mass of dimethyl silicone oil, 5% to 15% of the total mass of dimethyl silicone oil, and 2% of the total mass of dimethyl silicone oil in batches. Deionized water, knead and stir evenly; S2, heating and kneading; S3. Under the condition of vacuuming, continue to heat up, knead and degas to obtain modified white carbon black base material.

5. The wide-adhesion, low-modulus, high-elastic transparent dealcoholized silicone rubber according to claim 4, characterized in that: In step S1, the viscosity of the dimethyl silicone oil is 50 mPa·s to 2000 mPa·s, and the modifier is one or both of 1,3-bisaminomethyl-1,1,3,3-tetramethyldisiloxane and 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane.

6. The wide-adhesion, low-modulus, high-elastic transparent dealcoholized silicone rubber according to claim 5, characterized in that: The silane crosslinking agent is at least one of methyltriethoxysilane, vinyltriethoxysilane, propyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane and n-dodecyltriethoxysilane.

7. The wide-adhesion, low-modulus, high-elastic transparent dealcoholized silicone rubber according to claim 6, characterized in that: The silane coupling agent is at least one of γ-aminopropyltriethoxysilane, N-β-(aminoethyl)-γaminopropylmethyldimethoxysilane, N-β-(aminoethyl)-γaminopropylmethyldiethoxysilane, and N-(β-aminoethyl)-γ-aminopropyltriethoxysilane.

8. The wide-adhesion, low-modulus, high-elastic transparent dealcoholized silicone rubber according to claim 7, characterized in that: The catalyst is an organic tin catalyst, and specifically at least one of dibutyltin dilaurate, dioctyltin dilaurate, dibutyltin dicaprate and dibutyltin bis(acetylacetonate) can be selected.

9. A method for preparing a wide-adhesion, low-modulus, high-elastic transparent dealcoholization silicone rubber according to any one of claims 1 to 8, characterized in that: The steps include: Step 1: adding methyl-terminated diethoxy polydimethylsiloxane, a flexible polymer and a modified white carbon black base material into a high-speed disperser, and vacuuming and stirring to obtain a system I; Step 2: adding a silane crosslinking agent and a silane coupling agent into system I, vacuuming and stirring to obtain system II; Step 3: Add the catalyst into system II, evacuate and stir to obtain a transparent dealcoholized silicone rubber with wide adhesion, low modulus and high elasticity.

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