Flame-retardant polyurethane sealant

Abstract

The invention provides a flame-retardant polyurethane sealant, which is prepared by the following steps of: dehydrating quantitative flame-retardant polyol in a stirring reaction kettle for about 60 minutes at the temperature of 110 DEG C in vacuum, cooling to 55 DEG C, adding 3-isocyanate propyl trimethoxy silane in a molar ratio of 1: 1 to the flame-retardant polyol into the mixture, and stirring at the temperature of 110 DEG C for 10 minutes to obtain the flame-retardant polyurethane sealant. Reacting for 90 minutes in a nitrogen atmosphere, and then defoaming for 60 minutes in vacuum at 60 DEG C; the flame-retardant polyol is prepared from vinyl ethyl phosphate, vinyl isobutyl phosphate, 3-methyl-1, 5-pentanediol, 2-methyl-1, 3-propylene glycol, epoxypropane and ethylene oxide through a multi-step polymerization reaction in the presence of a catalyst, and the flame-retardant polyol is prepared from the vinyl ethyl phosphate, the vinyl isobutyl phosphate, the 3-methyl-1, 5-pentanediol, the 2-methyl-1, 3-propylene glycol, the epoxypropane and the ethylene oxide. According to the flame-retardant polyurethane sealant disclosed by the invention, the polyurethane sealant containing the self-made flame-retardant polyol can meet the flame retardant property UL94 V-0, the tensile strength is greater than 4.5 Mpa, and the flame-retardant polyurethane sealant does not contain halogen.

Description

Technical Field

[0001] The invention relates to the technical field of sealants, in particular to a flame retardant polyurethane sealant. Background Art

[0002] Polyurethane sealant is made of polyurethane prepolymer resin as the matrix, mixed with fillers, plasticizers, catalysts and other raw materials. It has good elasticity, high mechanical strength, good bonding and sealing, as well as excellent high and low temperature resistance, chemical resistance and other comprehensive properties. It is widely used in many industrial fields. The flame retardancy of sealants is also receiving more and more attention. Polyurethane sealants without flame retardant raw materials are not flame retardant, and the combustion process is accompanied by black smoke and dripping. Therefore, their application in occasions requiring flame retardant properties is limited. The way to improve the flame retardancy of sealants is to add raw materials with flame retardant functions, generally including solid powder and liquid materials. These raw materials contain elements such as nitrogen, phosphorus, and halogens. Through their own flame retardancy and the synergistic effect between different flame retardants, they achieve the purpose of flame retardancy.

[0003] Bonding and sealing of electronic components and assemblies such as electrical cabinets, hybrid integrated circuits, etc. Bonding and sealing of household appliances such as coffee pots, microwave ovens, heating tubes, etc. The fixing of components of the power supply on the power module of industrial appliances has specific requirements for the flame retardancy and bonding strength of the sealant. Therefore, there is a strong demand for the development of flame retardant polyurethane sealants in industrial applications.

[0004] In view of this, the present invention is proposed. Summary of the invention

[0005] The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art and provide a flame retardant polyurethane sealant.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] A flame retardant polyurethane sealant is prepared by dehydrating a quantitative amount of flame retardant polyol in a stirred reactor under vacuum at 110°C for about 60 minutes, then reducing the temperature to 55°C, adding 3-isocyanate propyl trimethoxysilane in a molar ratio of 1:1 to the polyol to the mixture, reacting in a nitrogen atmosphere for 90 minutes, and then degassing for 60 minutes under vacuum at 60°C; the flame retardant polyol comprises vinyl ethyl phosphate, vinyl isobutyl phosphate, 3-methyl-1,5-pentanediol, 2-methyl-1,3-propylene glycol, propylene oxide, and ethylene oxide, and is prepared by multi-step polymerization reaction in the presence of a catalyst.

[0008] Furthermore, the contents of vinyl ethyl phosphate, vinyl isobutyl phosphate, 3-methyl-1,5-pentanediol, 2-methyl-1,3-propanediol, propylene oxide and ethylene oxide are respectively 0%-40% for vinyl ethyl phosphate, 0%-45% for vinyl isobutyl phosphate, 0%-30% for 3-methyl-1,5-pentanediol, 0%-40% for 2-methyl-1,3-propanediol, 0%-50% for propylene oxide and 0%-42% for ethylene oxide.

[0009] Furthermore, the flame retardant polyol has a molecular weight of 18000-30000 g / mol.

[0010] Further, the preparation method of the flame retardant polyol is as follows: the vinyl ethyl phosphate, vinyl isobutyl phosphate, 3-methyl-1,5-pentanediol, 2-methyl-1,3-propanediol, and catalyst are stirred and dehydrated at 110-200° C. for 1-4 hours, then the temperature is raised to 210-270° C., and vacuumed until the vacuum degree is below -0.099 MPa, and then the temperature is set to 210-280° C. for transesterification reaction until the hydroxyl value is 8-14 mgKOH / g, and the reaction is terminated to obtain an intermediate. The intermediate, propylene oxide, and ethylene oxide are reacted at a temperature of 210-270° C., a pressure of 0.3-0.6 MPa, and a reaction time of 16-48 hours until the hydroxyl value is 3.5-6 mgKOH / g of the polyol.

[0011] The present invention also discloses a method for preparing the flame retardant polyurethane sealant, comprising the following steps:

[0012] Stir and dehydrate vinyl ethyl phosphate, vinyl isobutyl phosphate, 3-methyl-1,5-pentanediol, 2-methyl-1,3-propanediol, and catalyst at 110-200°C for 1-4h, then heat to 210-270°C, evacuate until the vacuum is below -0.099Mpa, then set the temperature to 210-280°C for transesterification until the hydroxyl value is 8-14mgKOH / g, terminate the reaction, and obtain an intermediate. Make the intermediate, propylene oxide, and ethylene oxide react at a temperature of 210-270°C, a pressure of 0.3-0.6Mpa, and a reaction time of 16-48h until a polyol with a hydroxyl value of 3.5-6mgKOH / g is obtained;

[0013] Dehydrate a certain amount of flame retardant polyol in a stirred reactor under vacuum at 110°C for about 60 minutes, and then reduce the temperature to 55°C;

[0014] 3-isocyanatepropyltrimethoxysilane in a molar ratio of 1:1 to polyol is added to the mixture, reacted in a nitrogen atmosphere for 90 minutes, and then degassed under vacuum at about 60° C. for 60 minutes to obtain the product.

[0015] The invention also discloses a processed product obtained by using the flame retardant polyurethane sealant

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: the present invention provides a flame retardant polyurethane sealant, the polyurethane sealant containing a self-made flame retardant polyol can meet the flame retardant performance UL94 V-0, the tensile strength is greater than 4.5Mpa, and the flame retardant polyurethane sealant does not contain halogen. DETAILED DESCRIPTION

[0017] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0018] Example 1

[0019] This embodiment provides a flame retardant polyurethane sealant.

[0020] The flame retardant polyester polyol is prepared by the following method: 400g of vinyl ethyl phosphate, 185g of 3-methyl-1,5-pentanediol and 0.01g of a homemade catalyst are sequentially introduced into a reactor, stirring is turned on, the temperature is set to 170°C for 1.5h for dehydration, the temperature is raised to 220°C for 24h and then restored to normal pressure, small molecular monomers are removed by a distillation tower, the temperature is lowered to 130°C, the material is discharged and stored, and an intermediate with a hydroxyl value of 13mgKOH / g is obtained. 100g of the intermediate is added to a reactor, the temperature is set to 220°C, the pressure is 0.3Mpa, 55g of propylene oxide is continuously introduced, and after reacting for 18h, a flame retardant polyol A with a hydroxyl value of 4.5mgKOH / g is obtained.

[0021] The method for preparing a flame retardant polyurethane sealant by mixing flame retardant polyester polyol A with 3-isocyanate propyltrimethoxysilane is as follows: a certain amount of polyol is dehydrated in a stirred reactor under vacuum at a temperature of 110°C for about 60 minutes, and then the temperature is reduced to 55°C, and 3-isocyanate propyltrimethoxysilane is added to the mixture in a molar ratio of 1:1 to the polyol, and the mixture is reacted in a nitrogen atmosphere for 90 minutes, and then degassed at a vacuum of about 60°C for 60 minutes. After the reaction is completed, the hot melt adhesive is loaded into a dry container made of aluminum, tin or its composite film.

[0022] Example 2

[0023] This embodiment provides a flame retardant polyurethane sealant.

[0024] The flame retardant polyester polyol is prepared by the following method: 130g of vinyl ethyl phosphate, 260g of vinyl isobutyl phosphate, 175g of 3-methyl-1,5-pentanediol and 0.012g of a homemade catalyst are sequentially introduced into a reactor, stirring is turned on, the temperature is set to 175°C for 1h for dehydration, the temperature is raised to 230°C for 24h and then restored to normal pressure, small molecular monomers are removed by a distillation tower, the temperature is lowered to 130°C, the material is discharged and stored, and an intermediate with a hydroxyl value of 9mgKOH / g is obtained. 120g of the intermediate is added to a reactor, the temperature is set to 220°C, the pressure is 0.5Mpa, 50g of propylene oxide and 12g of ethylene oxide are continuously introduced, and a flame retardant polyol B with a hydroxyl value of 5mgKOH / g is obtained after reacting for 15h.

[0025] The method for preparing a flame retardant polyurethane sealant by mixing flame retardant polyester polyol B with 3-isocyanate propyltrimethoxysilane is as follows: a certain amount of polyol is dehydrated in a stirred reactor under vacuum at a temperature of 110°C for about 60 minutes, and then the temperature is reduced to 55°C, and 3-isocyanate propyltrimethoxysilane is added to the mixture in a molar ratio of 1:1 to the polyol, and the mixture is reacted in a nitrogen atmosphere for 90 minutes, and then degassed at a vacuum of about 60°C for 60 minutes. After the reaction is completed, the hot melt adhesive is loaded into a dry container made of aluminum, tin or its composite film.

[0026] Example 3

[0027] This embodiment provides a flame retardant polyurethane sealant.

[0028] 400g of vinyl ethyl phosphate, 60g of 2-methyl-1,3-propylene glycol, 85g of 3-methyl-1,5-pentanediol and 0.005g of a homemade catalyst were introduced into the reactor in sequence, stirring was turned on, the temperature was set to 145°C for 2h for dehydration, the temperature was raised to 210°C for 36h and then restored to normal pressure, small molecular monomers were removed by a distillation tower, the temperature was lowered to 130°C, the material was discharged and stored, and an intermediate with a hydroxyl value of 8mgKOH / g was obtained. 100g of the intermediate was added to the reactor, the temperature was set to 210°C, the pressure was 0.4Mpa, 30g of propylene oxide and 42g of ethylene oxide were continuously introduced, and a flame retardant polyol C with a hydroxyl value of 3.5mgKOH / g was obtained after the reaction for 30h.

[0029] The method for preparing a flame retardant polyurethane sealant by mixing flame retardant polyester polyol C with 3-isocyanate propyltrimethoxysilane is as follows: a certain amount of polyol is dehydrated in a stirred reactor under vacuum at a temperature of 110°C for about 60 minutes, and then the temperature is reduced to 55°C, 3-isocyanate propyltrimethoxysilane is added to the mixture in a molar ratio of 1:1 to the polyol, and the mixture is reacted in a nitrogen atmosphere for 90 minutes, and then degassed at a vacuum of about 60°C for 60 minutes. After the reaction is completed, the hot melt adhesive is loaded into a dry container made of aluminum, tin or its composite film.

[0030] Example 4

[0031] This embodiment provides a flame retardant polyurethane sealant.

[0032] 380g of vinyl isobutyl phosphate, 100g of 2-methyl-1,3-propylene glycol, 40g of 3-methyl-1,5-pentanediol and 0.01g of a homemade catalyst were introduced into the reactor in sequence, stirring was turned on, the temperature was set to 155°C for 1h for dehydration, the temperature was raised to 220°C for 30h and then restored to normal pressure, small molecular monomers were removed by a distillation tower, the temperature was lowered to 130°C, the material was discharged and stored, and an intermediate with a hydroxyl value of 10mgKOH / g was obtained. 130g of the intermediate was added to the reactor, the temperature was set to 220°C, the pressure was 0.55Mpa, 60g of propylene oxide was continuously introduced, and after reacting for 30h, a flame retardant polyol D with a hydroxyl value of 4mgKOH / g was obtained.

[0033] The method for preparing a flame retardant polyurethane sealant by mixing flame retardant polyester polyol D with 3-isocyanate propyltrimethoxysilane is as follows: a certain amount of polyol is dehydrated in a stirred reactor under vacuum at a temperature of 110°C for about 60 minutes, and then the temperature is reduced to 55°C, 3-isocyanate propyltrimethoxysilane is added to the mixture in a molar ratio of 1:1 to the polyol, and the mixture is reacted in a nitrogen atmosphere for 90 minutes, and then degassed at a vacuum of about 60°C for 60 minutes. After the reaction is completed, the hot melt adhesive is loaded into a dry container made of aluminum, tin or its composite film.

[0034] Example 5

[0035] This embodiment provides a flame retardant polyurethane sealant.

[0036] 300g of vinyl ethyl phosphate, 90g of vinyl isobutyl phosphate, 110g of 2-methyl-1,3-propanediol, 25g of 3-methyl-1,5-pentanediol and 0.012g of a homemade catalyst were introduced into the reactor in sequence, stirring was turned on, the temperature was set to 165°C for 1h for dehydration, the temperature was raised to 235°C for 22h and then restored to normal pressure, small molecular monomers were removed by a distillation tower, the temperature was reduced to 130°C, the material was discharged and stored, and an intermediate with a hydroxyl value of 9mgKOH / g was obtained. 120g of the intermediate was added to the reactor, the temperature was set to 200°C, the pressure was 0.45Mpa, 40g of propylene oxide and 24g of ethylene oxide were continuously introduced, and a flame retardant polyol E with a hydroxyl value of 4.5mgKOH / g was obtained after the reaction for 16h.

[0037] The method for preparing a flame retardant polyurethane sealant by mixing flame retardant polyester polyol E with 3-isocyanate propyltrimethoxysilane is as follows: a certain amount of polyol is dehydrated in a stirred reactor under vacuum at a temperature of 110°C for about 60 minutes, and then the temperature is reduced to 55°C, and 3-isocyanate propyltrimethoxysilane is added to the mixture in a molar ratio of 1:1 to the polyol, and the mixture is reacted in a nitrogen atmosphere for 90 minutes, and then degassed at a vacuum of about 60°C for 60 minutes. After the reaction is completed, the hot melt adhesive is loaded into a dry container made of aluminum, tin or its composite film.

[0038] After the reaction is completed, the sealant is tested and the relevant data are as follows:

[0039]

[0040]

[0041] ①Test standard GB / T 13477-2002

[0042] ②Test standard GB / T 29595-2013

[0043] ③Test standard GB / T 528-2009

[0044] ③Tested according to UL 94 method.

[0045] It should be noted that the above description of these embodiments is used to help understand the present invention, but does not constitute a limitation of the present invention. In addition, the technical features involved in the various embodiments of the present invention described above can be combined with each other as long as they do not conflict with each other. In addition, the above are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work belong to the scope of protection of the present invention.

Claims

1. A flame retardant polyurethane sealant, characterized in that: The polyurethane sealant is prepared by dehydrating a quantitative amount of flame-retardant polyol in a stirred reactor under vacuum at a temperature of 110° C. for about 60 minutes, then reducing the temperature to 55° C., adding 3-isocyanate propyltrimethoxysilane in a molar ratio of 1:1 to the flame-retardant polyol to the mixture, reacting in a nitrogen atmosphere for 90 minutes, and then degassing for 60 minutes under vacuum at 60° C.; the flame-retardant polyol includes vinyl ethyl phosphate, vinyl isobutyl phosphate, 3-methyl-1,5-pentanediol, 2-methyl-1,3-propylene glycol, propylene oxide, and ethylene oxide, and is prepared by multi-step polymerization reaction in the presence of a catalyst.

2. A flame retardant polyurethane sealant as claimed in claim 1, characterized in that: Vinyl ethyl phosphate, vinyl isobutyl phosphate, 3-methyl-1,5-pentanediol, 2-methyl-1,3-propanediol, propylene oxide, and ethylene oxide contents are respectively 0%-40% for vinyl ethyl phosphate, 0%-45% for vinyl isobutyl phosphate, 0%-30% for 3-methyl-1,5-pentanediol, 0%-40% for 2-methyl-1,3-propanediol, 0%-50% for propylene oxide, and 0%-42% for ethylene oxide.

3. A flame retardant polyurethane sealant as claimed in claim 1, characterized in that: The molecular weight of the flame retardant polyol is 18000-30000 g / mol.

4. A flame retardant polyurethane sealant as claimed in claim 1, characterized in that: The preparation method of the flame retardant polyol is as follows: the vinyl ethyl phosphate, vinyl isobutyl phosphate, 3-methyl-1,5-pentanediol, 2-methyl-1,3-propanediol and catalyst are stirred and dehydrated at 110-200°C for 1-4 hours, then the temperature is raised to 210-270°C, and vacuum is drawn until the vacuum degree is below -0.099Mpa, and then the temperature is set to 210-280°C for transesterification reaction until the hydroxyl value is 8-14 mgKOH / g, and the reaction is terminated to obtain an intermediate. The intermediate, propylene oxide and ethylene oxide are reacted at a temperature of 210-270°C, a pressure of 0.3-0.6Mpa, and a reaction time of 16-48 hours until the hydroxyl value is 3.5-6 mgKOH / g of the polyol.

5. A method for preparing the flame retardant polyurethane sealant according to any one of claims 1 to 4, characterized in that: The following steps are involved: Stir and dehydrate vinyl ethyl phosphate, vinyl isobutyl phosphate, 3-methyl-1,5-pentanediol, 2-methyl-1,3-propanediol, and catalyst at 110-200°C for 1-4h, then heat to 210-270°C, evacuate until the vacuum is below -0.099Mpa, then set the temperature to 210-280°C for transesterification until the hydroxyl value is 8-14 mgKOH / g, terminate the reaction, and obtain an intermediate. Make the intermediate, propylene oxide, and ethylene oxide react at a temperature of 210-270°C, a pressure of 0.3-0.6Mpa, and a reaction time of 16-48h until a polyol with a hydroxyl value of 3.5-6 mgKOH / g is obtained; Dehydrate the flame retardant polyol in a stirred reactor under vacuum at 110°C for about 60 minutes, then reduce the temperature to 55°C; 3-isocyanatepropyltrimethoxysilane in a molar ratio of 1:1 to polyol is added to the mixture, reacted in a nitrogen atmosphere for 90 minutes, and then degassed under vacuum at about 60° C. for 60 minutes to obtain the product.

6. A processed product obtained by using the flame retardant polyurethane sealant according to any one of claims 1 to 5.

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