阅读说明：本技术 一种储存期较长的脱醇型透明硅酮密封胶 (Dealcoholized transparent silicone sealant with long storage life ) 是由 肖坤林 于 2019-11-29 设计创作，主要内容包括：本发明公开了一种储存期较长的脱醇型透明硅酮密封胶,涉及密封胶领域,按质量份,该透明硅酮密封胶包括100份烷氧基化聚二硅氧烷聚合物、10～20份亲水型白炭黑、0.5～15份甲氧基硅烷、0.2～10份氧醚、0.8～10份增粘稳定剂、0.05～0.3份有机锡催化剂、0～40份增塑剂和促进剂。本发明中的氧醚在能够增加亲水型白炭黑和疏水型封端有机硅材料有机硅材料的兼容性,促进亲水型白炭黑和疏水型封端有机硅材料快速反应,使烷氧基硅烷能够迅速高效和亲水型白炭黑中的水分反应并转化低级醇类,低级醇类可以通过真空完全除去,从而快速有效去除水分,且成本较低。(The invention discloses a dealcoholized transparent silicone sealant with a long storage life, which relates to the field of sealants and comprises, by mass, 100 parts of an alkoxylated polydisiloxane polymer, 10-20 parts of hydrophilic white carbon black, 0.5-15 parts of methoxysilane, 0.2-10 parts of oxygen ether, 0.8-10 parts of a tackifying stabilizer, 0.05-0.3 part of an organic tin catalyst, 0-40 parts of a plasticizer and an accelerator. The oxygen ether can increase the compatibility of hydrophilic white carbon black and hydrophobic end-capped organosilicon material, promote the quick reaction of the hydrophilic white carbon black and the hydrophobic end-capped organosilicon material, ensure that the alkoxy silane can quickly and efficiently react with the moisture in the hydrophilic white carbon black and convert into lower alcohols, and the lower alcohols can be completely removed through vacuum, so that the moisture can be quickly and effectively removed, and the cost is low.)

1. The dealcoholized transparent silicone sealant with long storage life is characterized by comprising the following components in parts by weight: comprises the following components in parts by mass:

2. the sealant according to claim 1, wherein the sealant comprises: the oxygen ether is one or a mixture of a plurality of methyl ethers.

3. The sealant according to claim 2, wherein the sealant comprises: the oxygen ether is ethylene glycol methyl ether or/and propylene glycol methyl ether.

4. The sealant according to claim 1, wherein the sealant comprises: the methoxysilane is methyltrimethoxysilane or vinyl trimethoxysilane.

5. The sealant according to claim 1, wherein the sealant comprises: the base polymer of the alkoxylated polydisiloxane polymer is alkoxylated polydisiloxane and is end-capped with methyltrimethoxysilane or vinyltrimethoxysilane.

6. The sealant according to claim 1, wherein the sealant comprises: the tackifying stabilizer is isocyanate silane.

7. The sealant according to claim 1, wherein the sealant comprises: the sealant also comprises an accelerator, wherein the accelerator is tetramethylguanidine.

8. The sealant according to claim 1, wherein the sealant comprises: the sealant also comprises 0-40 parts of a plasticizer, and the plasticizer is dimethyl silicone oil or No. 3 white oil.

9. The sealant according to claim 1, wherein the sealant comprises: the specific surface area of the hydrophilic white carbon black is 150-250 m²/g。

Technical Field

The invention relates to the field of sealants, in particular to a dealcoholized transparent silicone sealant with a long storage life.

Background

The dealcoholized transparent silicone sealant (hereinafter abbreviated as 'RTV 1') has the advantages of no peculiar smell, good adhesion, no corrosion to metal, adjustable curing speed and the like, is widely used, and can be stably stored for at least 6 months in the absence of moisture and quickly cured into a non-sticky elastomer when being contacted with the moisture by using the RTV 1.

The main components of a typical RTV mixture are usually based on polydimethylsiloxane terminated by dialkoxyalkyl and silyl groups, the filler is white-phase silica, the cross-linking agent is methyltrimethoxysilane, the metal catalyst is titanium or tin compound, the polydimethylsiloxane polyalkoxy of the silyl end group can be cross-linked by moisture in the atmosphere, and the white-phase silica contains a certain amount of moisture, so that the dispersibility of the white-phase silica is poor, the storage stability is influenced, and the storage period is shortened.

Early single-component RTV1 used polysiloxanes mostly containing methyltriacetoxysilane or methyltributanonoximosilane which released acetic acid and butanone oxime upon curing, acetic acid had a strong odor, and butanone oxime had a potential carcinogenic property, not only polluting the environment, but also being harmful to the human body.

In subsequent developments, the acyloxy and ketoxime groups were progressively replaced by alkoxy groups, however, compositions containing alkoxy groups would be converted during storage to hydroxyl functional containing materials such as monoalkoxydialkylsilyl terminated siloxanes, which would decompose to produce polysiloxanes and deactivate the catalyst when contacted with a metal catalyst. The main reason is that during the storage process, free methanol in the system and the metal catalyst generate a synergistic effect, and the subsequent reaction of the hydroxyl functional substance generates a byproduct which can not be crosslinked, so that the material is cured slowly or even fails.

U.S. Pat. No.5828200 discloses an improved polyalkoxysilyl-containing terminated RTV which uses silicon nitrogen or epoxy silane as a hydroxyl and moisture scavenger, however, both silicon nitrogen and epoxy silane are difficult to prepare and expensive, and the reaction of silicon nitrogen with hydroxyl generates nitrogen and other by-products, which not only has unpleasant taste, but also can corrode equipment or substrates; when the alkoxysilane is used as the hydroxyl and moisture scavenger, the alkoxysilane has a low hydrolysis rate and poor compatibility with moisture, so that the efficiency in treating the hydrophilic white carbon black moisture is low, and methanol generated after hydrolysis has a fatal influence on the storage of the alcohol-type gum.

The document "hydrophobic treatment of silica by dimethyldimethoxysilane" proposes that the efficiency is high and the hydrophobic rate reaches 100% when the dimethyldimethoxysilane is used for treating the white carbon black under the condition of trace amine, but the raw material of the dimethyldimethoxysilane is not easy to obtain and has higher price.

Disclosure of Invention

Aiming at the defects in the prior art, the invention aims to provide the dealcoholized transparent silicone sealant with long storage life, which can quickly and effectively remove water and has low cost.

In order to achieve the above purposes, the technical scheme adopted by the invention is as follows:

the dealcoholized transparent silicone sealant with long storage life comprises the following components in parts by mass:

further, the oxygen ether is one methyl ether or a mixture of a plurality of methyl ethers.

Further, the oxygen ether is ethylene glycol methyl ether or/and propylene glycol methyl ether.

Further, the methoxysilane is methyltrimethoxysilane or vinyl trimethoxysilane.

Further, the base polymer of the alkoxylated polydisiloxane polymer is an alkoxylated polydisiloxane and is end-capped with methyltrimethoxysilane or vinyltrimethoxysilane.

Furthermore, the tackifying stabilizer is isocyanate silane.

Furthermore, the sealant also comprises an accelerator, wherein the accelerator is tetramethylguanidine.

Further, the sealant also comprises 0-40 parts of a plasticizer, and the plasticizer is dimethyl silicone oil or No. 3 white oil.

Further, the specific surface area of the hydrophilic white carbon black is 150-250 m²/g。

Compared with the prior art, the invention has the advantages that:

(1) according to the dealcoholization type transparent silicone sealant with a long storage life, the oxygen ether can increase the compatibility of hydrophilic white carbon black and a hydrophobic end-capped organosilicon material, and simultaneously promote the quick reaction of the hydrophilic white carbon black and the hydrophobic end-capped organosilicon material, so that the alkoxysilane can quickly and efficiently react with water in the hydrophilic white carbon black and convert into lower alcohols, the lower alcohols are usually formed at a temperature as low as 10-25 ℃, and can be completely removed through vacuum at a temperature of 50-65 ℃.

Meanwhile, the tackifying stabilizer isocyanate silane in the embodiment can react with free methanol slowly generated in the storage period, and the phenomenon that the free methanol and an organic tin catalyst generate a synergistic effect to cause a hydroxyl functional group to react to generate a crosslinking byproduct is avoided, so that the curing failure of the material in the storage process is prevented, the effectiveness of the transparent silicone sealant in the storage process is maintained, and the quality guarantee period of the transparent silicone sealant is prolonged.

(2) According to the dealcoholization type transparent silicone sealant with a long storage life, the difference between the initial surface drying time of the dealcoholization type transparent silicone sealant using the oxygen ether and the comparative example not added is smaller, but after an aging experiment at 100 ℃ for one day, 50 ℃ for one month, 25 ℃ for six months and 25 ℃ for one year, the surface drying time of the sealant without the oxygen ether is far longer than that of the sealant added with the oxygen ether, the stability of the sealant added with the oxygen ether is better, the sealant still has a faster surface drying time after the aging experiment and can be better cured, the surface drying time of the sealant without the oxygen ether is obviously prolonged, the curing depth is reduced, and even the sealant cannot be cured, so that the dealcoholization type transparent silicone sealant prepared by the embodiment of the invention has better storage stability.

Detailed Description

The following examples of the present invention are described in further detail.

The embodiment of the invention provides a dealcoholization type transparent silicone sealant with a long storage life, which comprises, by mass, 100 parts of an alkoxylated polydisiloxane polymer, 10-20 parts of hydrophilic white carbon black, 0.5-15 parts of methoxysilane, 0.2-10 parts of oxygen ether, 0.8-10 parts of a tackifying stabilizer, 0.05-0.3 part of an organic tin catalyst, 0-40 parts of a plasticizer and an accelerator.

Wherein the specific surface area of the hydrophilic white carbon black is 150-250 m²(ii)/g, water content 3%; the oxygen ether is one or a mixture of a plurality of methyl ethers, and in the invention, the oxygen ether is ethylene glycol methyl ether or/and propylene glycol methyl ether.

The methoxysilane is methyltrimethoxysilane or vinyl trimethoxysilane; the base polymer of the alkoxylated polydisiloxane polymer is alkoxylated polydisiloxane, methyl trimethoxy silane or vinyl trimethoxy silane is used for blocking, the tackifying stabilizer is isocyanate silane, the plasticizer is dimethyl silicone oil or No. 3 white oil, and the accelerator is tetramethyl guanidine.

In actual use, the using amount of the hydrophilic white carbon black, the methoxysilane, the oxygen ether, the tackifying stabilizer, the organic tin catalyst and the plasticizer can be adjusted according to actual needs, for example, the hydrophilic white carbon black can be 12-16 parts, the methoxysilane can be 5-10 parts, the oxygen ether can be 3-6 parts, the tackifying stabilizer can be 2-6 parts, the organic tin catalyst can be 0.1-0.2 part, and the plasticizer can be 10-20 parts.

In the embodiment of the invention, the oxygen ether can increase the compatibility of hydrophilic white carbon black and hydrophobic end-capped organosilicon material (oxidized polydisiloxane polymer), and simultaneously promote the quick reaction of the hydrophilic white carbon black and the hydrophobic end-capped organosilicon material, so that the alkoxysilane can quickly and efficiently react with the moisture in the hydrophilic white carbon black and convert into lower alcohols, the lower alcohols are usually formed at the temperature of 10-25 ℃, and can be completely removed by vacuum at the temperature of 50-65 ℃.

Meanwhile, the tackifying stabilizer isocyanate silane in the embodiment can react with free methanol slowly generated in the storage period, and the phenomenon that the free methanol and an organic tin catalyst generate a synergistic effect to cause a hydroxyl functional group to react to generate a crosslinking byproduct is avoided, so that the curing failure of the material in the storage process is prevented, the effectiveness of the transparent silicone sealant in the storage process is maintained, and the quality guarantee period of the transparent silicone sealant is prolonged.

The principle is as follows: the oxygen ether can eliminate an interface layer of methoxysilane and water, and the hydrolysis reaction can rapidly occur to generate methanol under the condition of the existence of tetramethylguanidine. In the embodiment of the invention, after the methoxysilane (methyltrimethoxysilane or vinyl trimethoxysilane) is mixed with water, the interface layer between the methoxysilane and the water is still clear after the mixture is stored for one week; the interfacial layer disappears in a few seconds after the addition of the oxygen ether, methoxysilane and water are completely hydrolyzed within 5 minutes in the presence of tetramethylguanidine, and simultaneously, the tetramethylguanidine can promote the curing speed of the sealant in the atmosphere when the transparent silicone sealant is used specifically.

The present invention will be described in detail below with reference to 8 examples and comparative examples.