阅读说明：本技术 一种硅烷封端聚醚密封胶及其制备方法 (Silane-terminated polyether sealant and preparation method thereof ) 是由 高群 雷曼云 翟淑宁 汤明长 张伦生 于 2019-11-01 设计创作，主要内容包括：本发明公开了一种硅烷封端聚醚密封胶及其制备方法。所述密封胶包括短链硅烷封端聚醚多元醇,长链硅烷封端聚醚多元醇,增塑剂,碳酸钙,气相白炭黑,有机硅消泡剂,硅烷偶联剂及有机锡催化剂。制备方法为：将短链硅烷封端聚醚多元醇、长链硅烷封端聚醚多元醇、增塑剂、碳酸钙和气相白炭黑加入到行星搅拌釜中,搅拌混合均匀；然后加入硅烷偶联剂和有机硅消泡剂,抽真空并搅拌混合均匀；解除真空环境后加入有机锡催化剂,再次抽真空并搅拌混合均匀,即得到硅烷封端聚醚密封胶。本发明制备的硅烷封端聚醚密封胶具有高拉伸强度和断裂伸长率,优良的耐候性、耐久性、高的抗形变位移能力。(The invention discloses a silane-terminated polyether sealant and a preparation method thereof. The sealant comprises short-chain silane-terminated polyether polyol, long-chain silane-terminated polyether polyol, a plasticizer, calcium carbonate, fumed silica, an organic silicon defoaming agent, a silane coupling agent and an organic tin catalyst. The preparation method comprises the following steps: adding short-chain silane-terminated polyether polyol, long-chain silane-terminated polyether polyol, a plasticizer, calcium carbonate and fumed silica into a planetary stirring kettle, and uniformly stirring and mixing; then adding a silane coupling agent and an organic silicon defoaming agent, vacuumizing, stirring and mixing uniformly; and (3) after the vacuum environment is relieved, adding an organic tin catalyst, vacuumizing again, stirring and mixing uniformly to obtain the silane terminated polyether sealant. The silane-terminated polyether sealant prepared by the invention has high tensile strength and elongation at break, excellent weather resistance, durability and high deformation displacement resistance.)

1. The silane-terminated polyether sealant is characterized by comprising, by weight, 5-15 parts of short-chain silane-terminated polyether polyol, 20-30 parts of long-chain silane-terminated polyether polyol, 5-35 parts of plasticizer, 10-30 parts of calcium carbonate, 1-5 parts of fumed silica, 0.1-0.5 part of organic silicon defoamer, 0.5-1.5 parts of silane coupling agent and 0.1-0.3 part of organic tin catalyst.

2. The silane-terminated polyether sealant of claim 1 wherein the short/long chain silane-terminated polyether polyol is prepared by a process comprising the steps of:

step 1): selecting polyether polyols with different molecular weights according to short/long-chain silane-terminated polyether polyols, wherein one end of the polyether polyol is terminated with-OH, the other end of the polyether polyol is terminated with-C-, and the polyether polyol and a diisocyanate compound are mixed according to a molar ratio of (1-2): 1, adding the mixture into a reaction bottle, heating to 60-90 ℃, and reacting for 2-3 h under the protection of nitrogen to form a carbon-carbon double bond terminated prepolymer W;

step 2): C-C double bond end-capped prepolymer W and corresponding hydrogen-containing trimethoxy silane are mixed according to a molar ratio of 1: (1-2) adding the mixture into a reaction bottle, adding a chloroplatinic acid catalyst, wherein the concentration of the added chloroplatinic acid catalyst is 30-60 ppm, heating the mixture to 90-120 ℃, and reacting for 3-6 h under the protection of nitrogen to obtain the corresponding short/long chain silane end-capped polyether polyol.

3. The silane-terminated polyether sealant according to claim 1 or 2, wherein the short-chain silane-terminated polyether polyol has a number average molecular weight of 1000 to 2000 g/mol; the number average molecular weight of the long-chain silane-terminated polyether polyol is more than 9000 g/mol.

4. The silane-terminated polyether sealant according to claim 2, wherein the polyether polyol adopted by the short-chain silane-terminated polyether polyol is allyl alcohol polyoxyethylene ether or allyl alcohol polyoxypropylene ether with the number average molecular weight of 500-1000 g/mol; the polyether polyol adopted by the long-chain silane end-capped polyether polyol is any one of allyl alcohol polyoxyethylene ether, allyl alcohol polyoxypropylene ether and isoamylol polyoxyethylene ether with the number average molecular weight of 4000-6000 g/mol.

5. The silane-terminated polyether sealant according to claim 2, wherein the diisocyanate compound in step 2) is any one of toluene diisocyanate, diphenylmethane diisocyanate and isophorone diisocyanate.

6. The silane-terminated polyether sealant according to claim 1, wherein the plasticizer is any one of polypropylene glycol 2000, polypropylene glycol 3000 and dinonyl phthalate.

7. The silane-terminated polyether sealant according to claim 1, wherein the silicone antifoaming agent is any one of methyl silicone oil, methylphenyl silicone oil and polyether modified silicone oil.

8. The silane-terminated polyether sealant of claim 1, wherein the silane coupling agent is any one of gamma-aminopropyltriethoxysilane, gamma-glycidoxypropyltrimethoxysilane, and gamma- (methacryloyloxy) propyltrimethoxysilane.

9. The silane-terminated polyether sealant according to claim 1, wherein the organotin catalyst is any one of dibutyltin dilaurate, stannous octoate, and dibutyltin diacetate.

10. The preparation method of the silane-terminated polyether sealant as claimed in any one of claims 1 to 9, characterized in that the short-chain silane-terminated polyether polyol, the long-chain silane-terminated polyether polyol, the plasticizer, the calcium carbonate and the fumed silica are added into a planetary stirring kettle and stirred and mixed uniformly; then adding a silane coupling agent and an organic silicon defoaming agent, vacuumizing, stirring and mixing uniformly; and (3) after the vacuum environment is relieved, adding an organic tin catalyst, vacuumizing again, stirring and mixing uniformly to obtain the silane terminated polyether sealant.

Technical Field

The invention relates to a preparation method of a silane-terminated polyether sealant, belonging to the technical field of sealants.

Background

Both silicone sealants and polyurethane sealants are widely used, but they have some disadvantages, such as the silicone sealant easily contaminates the adjacent portion of the adhesive area and the surface finishing property is poor; the polyurethane sealant has pungent smell and is easy to generate bubbles. The silane-terminated polyether sealant is a novel silane-modified polyether sealant prepared by taking silane-terminated polyether (MS polymer) as a basic polymer. The MS polymer is structurally characterized in that the main chain is macromolecular polyether, the end group is silane containing hydrolyzable groups, the cross-linking point of the network structure after the MS sealant taking the MS polymer as a substrate is cured is a Si-O-Si bond, and macromolecular polyether long chains are arranged between the cross-linking point and the cross-linking point. The MS sealant has excellent weather resistance, durability, high deformation displacement resistance, good adhesion, coating property, environmental friendliness, low fouling property and excellent operation performance, and can be applied to a plurality of industrial fields. The silane modified polyether sealant is developed rapidly in China in recent years and has wide development space.

Patent CN109575869A discloses a single-component moisture-curing polyurethane sealant and a preparation method thereof, wherein the release of carbon dioxide is reduced by controlling the proportion of polyurethane resin, the crosslinking degree of polyurethane prepolymer is improved, the carbon dioxide is inhibited by the strength increase in the curing process of polyurethane adhesive, the sealant can be used for sealing glass seams of passenger cars, rail transit and ships, and the problem of swelling of the moisture-curing sealant cured under the high-temperature and high-humidity environment is solved.

Patent CN109536106A discloses a high-strength silane-modified polyether polymer and a preparation method thereof, wherein a low-molecular-weight polyether polyol, an epoxide and an epoxy silane coupling agent are subjected to a polymerization reaction under inert gas protection and anhydrous conditions and in the presence of a catalyst to obtain the silane-modified polyether polymer, and hydrolysable silane oxygen groups are on side chains of a polyether main chain, and a three-dimensional network structure with a higher cross-linking density can be formed after silane oxygen is hydrolyzed, cross-linked and cured, so as to improve tensile strength and bonding strength.

Disclosure of Invention

The technical problem to be solved by the invention is as follows: the technical problems of low strength, unstable structure, poor heat resistance and the like of the organic silicon sealant and the polyurethane sealant in the prior art are solved.

In order to solve the problems, the technical scheme adopted by the invention is as follows:

the silane-terminated polyether sealant is characterized by comprising, by weight, 5-15 parts of short-chain silane-terminated polyether polyol, 20-30 parts of long-chain silane-terminated polyether polyol, 5-35 parts of plasticizer, 10-30 parts of calcium carbonate, 1-5 parts of fumed silica, 0.1-0.5 part of organic silicon defoamer, 0.5-1.5 parts of silane coupling agent and 0.1-0.3 part of organic tin catalyst.

Preferably, the preparation method of the short/long-chain silane-terminated polyether polyol comprises the following steps:

step 1): selecting polyether polyols with different molecular weights according to short/long-chain silane-terminated polyether polyols, wherein one end of the polyether polyol is terminated with-OH, the other end of the polyether polyol is terminated with-C-, and the polyether polyol and a diisocyanate compound are mixed according to a molar ratio of (1-2): 1, adding the mixture into a reaction bottle, heating to 60-90 ℃, and reacting for 2-3 h under the protection of nitrogen to form a carbon-carbon double bond terminated prepolymer W;

step 2): C-C double bond end-capped prepolymer W and corresponding hydrogen-containing trimethoxy silane are mixed according to a molar ratio of 1: (1-2) adding the mixture into a reaction bottle, adding a chloroplatinic acid catalyst, wherein the concentration of the added chloroplatinic acid catalyst is 30-60 ppm, heating the mixture to 90-120 ℃, and reacting for 3-6 h under the protection of nitrogen to obtain the corresponding short/long chain silane end-capped polyether polyol.

Preferably, the number average molecular weight of the short-chain silane-terminated polyether polyol is 1000-2000 g/mol; the number average molecular weight of the long-chain silane-terminated polyether polyol is more than 9000 g/mol.

More preferably, the polyether polyol adopted by the short-chain silane-terminated polyether polyol is allyl alcohol polyoxyethylene ether or allyl alcohol polyoxypropylene ether with the number average molecular weight of 500-1000 g/mol; the polyether polyol adopted by the long-chain silane end-capped polyether polyol is any one of allyl alcohol polyoxyethylene ether, allyl alcohol polyoxypropylene ether and isoamylol polyoxyethylene ether with the number average molecular weight of 4000-6000 g/mol.

More preferably, the diisocyanate compound in step 2) is any one of toluene diisocyanate, diphenylmethane diisocyanate and isophorone diisocyanate.

Preferably, the plasticizer is any one of polypropylene glycol 2000, polypropylene glycol 3000 and dinonyl phthalate.

Preferably, the silicone defoamer is any one of methyl silicone oil, methyl phenyl silicone oil and polyether modified silicone oil.

Preferably, the silane coupling agent is any one of gamma-aminopropyltriethoxysilane, gamma-glycidoxypropyltrimethoxysilane and gamma- (methacryloyloxy) propyltrimethoxysilane.

Preferably, the organic tin catalyst is any one of dibutyltin dilaurate, stannous octoate and dibutyltin diacetate.

The invention also provides a preparation method of the silane-terminated polyether sealant, which is characterized by adding the short-chain silane-terminated polyether polyol, the long-chain silane-terminated polyether polyol, the plasticizer, the calcium carbonate and the fumed silica into a planetary stirring kettle, and uniformly stirring and mixing; then adding a silane coupling agent and an organic silicon defoaming agent, vacuumizing, stirring and mixing uniformly; and (3) after the vacuum environment is relieved, adding an organic tin catalyst, vacuumizing again, stirring and mixing uniformly to obtain the silane terminated polyether sealant.

Compared with the prior art, the invention has the beneficial effects that:

according to the invention, the silane-terminated polyether polyols with different molecular weights are selected, the use amounts of the filler and the plasticizer are adjusted, the mechanical property of the obtained silane modified sealant is improved, the elastic requirement is met, and the silane-modified sealant has a stress relaxation characteristic, under the condition of being in a stretching state for a long time, the corresponding tensile modulus can be gradually reduced through the stress relaxation effect, the internal stress of the sealant in a deformation state is reduced, the influence caused by the shrinkage of a building base material can be eliminated to the greatest extent, and the application range of a polyether product is effectively widened. Meanwhile, the filler used in the invention is large in dosage, so that the stress relaxation performance is promoted, the preparation cost is correspondingly reduced, and the economic benefit is better.

According to the invention, the short-chain silane-terminated polyether and the long-chain silane-terminated polyether polyol are used as basic polymers, and the adopted synthesis methods of the allyl polyether polyol and the isocyanate with different molecular weights can conveniently prepare the silane-terminated polyether polyol with high molecular weight, the preparation process is simple, the efficiency is high, the product performance is excellent, the number average molecular weight of the long-chain silane-terminated polyether polyol is more than 9000g/mol, and the sealant can obtain high tensile strength and high elongation at break due to higher molar mass.

Detailed Description

In order to make the invention more comprehensible, preferred embodiments are described in detail below.