Environment-friendly silane modified polyurethane compounded silane modified polyether sealant and preparation method thereof

Abstract

The invention discloses an environment-friendly silane modified polyurethane compounded silane modified polyether sealant and a preparation method thereof. The sealant is specifically prepared from the following components in parts by weight: 15 to 35 parts of silane modified polyurethane compounded silane modified polyether resin, 50 to 65 parts of inorganic filler, 10 to 20 parts of plasticizer, 0.3 to 0.6 part of adhesion promoter and 0.08 to 0.2 part of organic tin catalyst, according to the sealant provided by the invention, the silane modified polyurethane is compounded with the silane modified polyether resin, meanwhile, the sealant contains silane modified polyurethane and silane modified polyether resin structural units, meanwhile, the sealant has high curing speed and structural stability among macromolecules, and the sealant contains a multi-branched chain structure and can be widely bonded to a base material.

Description

Technical Field

[0001] This invention relates to the field of sealant technology, and more specifically, to an environmentally friendly silane-modified polyurethane compound silane-modified polyether sealant and its preparation method. Background Technology

[0002] There are several common types of sealants, including silicone and polyurethane-based sealants, as well as neoprene rubber-based all-purpose sealants and SBS resin-based sealants. SBS resin sealants contain toxic substances such as benzene, toluene, xylene, and vinyl chloride as solvents, making them extremely environmentally unfriendly and unhealthy. Silicone sealants release methyl ethyl ketone oxime during the curing process, a known carcinogen, and their use in automotive sealants should be restricted and gradually phased out. Polyurethane sealants contain diisocyanates, a contributing factor to leukemia, and their widespread use in the sealant industry is not recommended.

[0003] Currently, the synthesis processes for solvent-free, environmentally friendly silicone sealants mainly include silane-modified polyether and silane-modified polyurethane processes. The silane-modified polyether process uses difunctional resins, resulting in slow curing speeds, low hardness of the cured colloid, and limited application range. The silane-modified polyurethane process utilizes aliphatic long-chain resins with stable intermolecular structures, resistance to discoloration, and good mechanical properties; however, the aliphatic long-chain structure has fewer branches, limiting the range of substrates it can bond to and resulting in weak adhesion. There is an urgent need to develop an environmentally friendly sealant that offers broad substrate adhesion and rapid curing. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a silane-modified polyurethane compound silane-modified polyether sealant with extremely low VOC emissions, wide adhesion to substrates, fast curing speed, high bonding strength, and high weather resistance.

[0005] One of the objectives of this invention is to provide a silane-modified polyurethane compound with silane-modified polyether sealant.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A silane-modified polyurethane compound silane-modified polyether sealant is provided, comprising the following components in parts by weight:

[0008] 15-35 parts of silane-modified polyurethane compounded with silane-modified polyether resin.

[0009] 50-65 parts of inorganic filler

[0010] 10-20 parts plasticizer

[0011] Adhesion promoter 0.3-0.6 parts,

[0012] 0.08-0.2 parts of organotin catalyst;

[0013] The preparation method of the silane-modified polyurethane compound silane-modified polyether resin includes the following steps:

[0014] S1, low-molecular-weight polyether polyols with a molecular weight ≤5000 are added to polyisocyanate and organotin catalyst at 85-95℃ to carry out chain extension reaction to obtain prepolymer;

[0015] S2, add a high polyether polyol with a molecular weight ≥15000 to the prepolymer, add polyisocyanate at 90-100℃ for chain extension reaction, and when NCO% ≤1.0%, add terminal isocyanate silane and keep it at the temperature to obtain the silane-modified polyurethane compound silane-modified polyether resin.

[0016] In some embodiments, in the preparation method of the silane-modified polyurethane compounded with silane-modified polyether resin, the polyisocyanate is selected from diphenylmethane diisocyanate (MDI).

[0017] In some embodiments, in the preparation method of the silane-modified polyurethane compound silane-modified polyether resin, the molecular weight of the low-polyether polyol is 3000-5000; and the molecular weight of the high-polyether polyol is 16000-20000.

[0018] In some embodiments, the inorganic filler is selected from at least one of nano-calcium carbonate, fumed silica, and activated heavy calcium carbonate.

[0019] In some embodiments, the plasticizer is selected from at least one of PPG3000 and PPG4000.

[0020] In some embodiments, the adhesion promoter is selected from at least one of γ-aminopropyltriethoxysilane and N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane.

[0021] In some embodiments, the organotin catalyst is dilaurate butyltin.

[0022] In some embodiments, the mixture also includes: 0.2-0.4 parts of anti-aging agent, 0.8-1.5 parts of dehydrating agent, and 1-3 parts of colorant.

[0023] The dehydrating agent is selected from one or more of vinyltrimethoxysilane, methyltrimethoxysilane, and p-toluenesulfonyl isocyanate.

[0024] The colorant is rutile titanium dioxide or carbon black.

[0025] In some embodiments, the silane-modified polyurethane compound silane-modified polyether sealant has a viscosity of 75,000-85,000 mPa·s at 25°C.

[0026] A method for preparing a silane-modified polyurethane compound silane-modified polyether sealant is provided, characterized by comprising the following steps: stirring a plasticizer and an inorganic filler evenly, adding a silane-modified polyurethane compound silane-modified polyether resin and stirring evenly, adding the remaining components and statically mixing evenly to obtain the silane-modified polyurethane compound silane-modified polyether sealant.

[0027] In some embodiments, the static mixing involves using a static mixer to uniformly mix the materials at room temperature and pressure. This product uses a static mixer to add various materials, and the materials are transported entirely through pipelines, reducing contact with air and resulting in a finer product appearance compared to products produced by high-speed dispersers.

[0028] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0029] The silane-modified polyurethane compounded with silane-modified polyether sealant of the present invention contains both silane-modified polyurethane and silane-modified polyether resin structural units, exhibiting high curing speed, high intermolecular structural stability, and a multi-branched structure that enables broad adhesion to substrates. Through the synergistic effect of the components, it possesses high thixotropic properties, high mechanical properties, and durability. Detailed Implementation

[0030] To better illustrate the purpose, technical solution, and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments.

[0031] Unless otherwise specified, all raw materials used in this invention are commercially available.

[0032] The preparation method of the silane-modified polyurethane compounded with silane-modified polyether resin described in the following examples and comparative examples includes the following steps:

[0033] S1. The polyether polyol (PPG4000) with a molecular weight of 4000 was heated to 120°C and vacuum stirred for 120 min to remove water. Then, an appropriate amount of MDI and dilaurate butyltin were added at 90°C to carry out a chain extension reaction for 60 min. The diisocyanate content was determined to be ≤0.1% by the n-butylamine method (ASTM D2572-19) to obtain the prepolymer.

[0034] S2, add a polyether polyol (PPG18000) with a molecular weight of 18000 to the prepolymer, add an appropriate amount of MDI at 95°C and react for 120 min, and the diisocyanate content is ≤0.1%. Add an appropriate amount of γ-isocyanate propyltrimethoxysilane and react at a constant temperature for 180 min, and the isocyanate content is ≤0.1%, thus obtaining silane-modified polyurethane compounded with silane-modified polyether resin.

[0035] Examples 1-2

[0036] A silane-modified polyurethane compound silane-modified polyether sealant, the raw materials of which are shown in Table 1 by weight:

[0037] Table 1

[0038]

[0039] The preparation method of the silane-modified polyurethane compound silane-modified polyether sealant includes the following steps:

[0040] 1) Plasticizer and filler are uniformly mixed in a digitally controlled twin-screw mixer, and the mixture is dehydrated by a high-temperature negative pressure physical method under vacuum of -0.09MPa and 130℃ to obtain the first semi-finished product;

[0041] 2) In a high-speed disperser, the first semi-finished product, silane-modified polyurethane compounded with silane-modified polyether resin, dehydrating agent and anti-aging agent are uniformly mixed for 2 hours. The temperature is controlled below 75°C during mixing to obtain the second semi-finished product.

[0042] 3) In a static mixer, the second semi-finished product, colorant and adhesion promoter are uniformly mixed at room temperature and pressure to obtain the environmentally friendly silane-modified polyurethane compound silane-modified polyether sealant.

[0043] Performance testing

[0044] The samples from Examples 1-2 were subjected to the following performance tests, and the results are shown in Table 2:

[0045] Table 2

[0046]

[0047] The results show that the silane-modified polyurethane compounded with silane-modified polyether sealant of the present invention has the characteristics of fast curing speed, high adhesion and strong mechanical properties.

[0048] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A silane-modified polyurethane compounded with silane-modified polyether sealant, characterized in that, Includes the following components by weight: 15-35 parts of silane-modified polyurethane compounded with silane-modified polyether resin. 50-65 parts of inorganic filler 10-20 parts plasticizer Adhesion promoter 0.3-0.6 parts, 0.08-0.2 parts of organotin catalyst; The preparation method of the silane-modified polyurethane compound silane-modified polyether resin includes the following steps: S1, low-molecular-weight polyether polyols with a molecular weight ≤5000 are added to polyisocyanate and organotin catalyst at 85-95℃ to carry out chain extension reaction to obtain prepolymer; S2, add a high polyether polyol with a molecular weight ≥15000 to the prepolymer, add polyisocyanate at 90-100℃ for chain extension reaction, and when NCO% ≤1.0%, add terminal isocyanate silane and keep it at the temperature to obtain the silane-modified polyurethane compound silane-modified polyether resin.

2. The silane-modified polyurethane compound silane-modified polyether sealant according to claim 1, characterized in that, In the preparation method of the silane-modified polyurethane compound silane-modified polyether resin, the polyisocyanate is selected from diphenylmethane diisocyanate.

3. The silane-modified polyurethane compound silane-modified polyether sealant according to claim 1, characterized in that, In the preparation method of the silane-modified polyurethane compound silane-modified polyether resin, the molecular weight of the low polyether polyol is 3000-5000; and the molecular weight of the high polyether polyol is 16000-20000.

4. The silane-modified polyurethane compounded with silane-modified polyether sealant according to claim 1, characterized in that, The inorganic filler is selected from at least one of nano-calcium carbonate, fumed silica, and activated heavy calcium carbonate.

5. The silane-modified polyurethane compound silane-modified polyether sealant according to claim 1, characterized in that, The plasticizer is selected from at least one of PPG3000 and PPG4000.

6. The silane-modified polyurethane compounded with silane-modified polyether sealant according to claim 1, characterized in that, The adhesion promoter is selected from at least one of γ-aminopropyltriethoxysilane and N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane.

7. The silane-modified polyurethane compound silane-modified polyether sealant according to claim 1, characterized in that, The organotin catalyst is dilaurate butyltin.

8. The silane-modified polyurethane compound silane-modified polyether sealant according to claim 1, characterized in that, Also includes: Anti-aging agent 0.2-0.4 parts, dehydrating agent 0.8-1.5 parts, colorant 1-3 parts.

9. A method for preparing the silane-modified polyurethane compounded silane-modified polyether sealant according to any one of claims 1-8, characterized in that, The process includes the following steps: mixing the plasticizer and inorganic filler evenly, adding the silane-modified polyurethane compound silane-modified polyether resin and mixing evenly, adding the remaining components and statically mixing evenly to obtain the silane-modified polyurethane compound silane-modified polyether sealant.

10. The method for preparing the silane-modified polyurethane compounded silane-modified polyether sealant according to claim 9, characterized in that, The static mixing refers to mixing the materials evenly using a static mixer at normal temperature and pressure.

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