Anti-aging two-component polyurethane pouring sealant and preparation method thereof

Abstract

The invention discloses an anti-aging double-component polyurethane pouring sealant, which comprises a component A curing agent and a component B main glue, the ratio range of A: B is (10-120): 100, and the component B main glue comprises the following preparation raw materials by weight: 10-98 parts of polyol, 0-30 parts of a plasticizer I, 0-30 parts of a flame retardant I, 1-10 parts of an epoxy group compound, 0-75 parts of a filler, 0.01-0.1 part of an antifoaming agent, and 0.01-0.5 part of a molecular sieve. And 0.001 to 0.05 part of a catalyst. Different from an epoxy / polyurethane interpenetrating network structure, a polyfunctional epoxy diluent or low-viscosity epoxy resin is directly added into a polyurethane adhesive formula, an epoxy curing agent is not added, and the prepared polyurethane pouring sealant has excellent aging resistance in a high-temperature and high-humidity environment.

Description

Technical Field

[0001] The invention relates to an aging-resistant two-component polyurethane potting adhesive and a preparation method thereof, and relates to C09J, in particular to the field of adhesives. Background Art

[0002] Polyurethane potting glue can be used in electronic devices to seal electronic devices. As the application range of electronic devices expands, polyurethane potting glue needs to be used in more severe environments. When the existing polyurethane potting glue is used in a high temperature and high humidity environment, the surface of the polyurethane potting glue will liquefy, the service life of the polyurethane potting glue will be shortened, and the sealing effect will decrease. Therefore, it is very important to develop a polyurethane potting glue with a long service life in a high temperature and high humidity environment.

[0003] Chinese invention patent CN202011153945.9 discloses a high-insulation, low-temperature resistant expansion flame-retardant polyurethane material and its preparation method and application. By using halogen-free flame retardants, the prepared polyurethane potting glue can instantly expand and foam significantly under the action of heat or open flames to prevent the spread of fire, and can play a good role in fire prevention and heat insulation. It has good lasting adhesion to substrates such as cables, metals, and concrete, a long service life, good air tightness and insulation at room temperature and low temperature, and good acid and alkali resistance and chemical corrosion resistance. However, it is not effective in high temperature and high humidity environments. Chinese invention patent CN201910148774.1 discloses a two-component low-hardness heat-resistant polyurethane potting glue and its preparation method. By introducing polyolefin polyols, the prepared polyurethane potting glue has low hardness and excellent heat resistance, but the heat resistance temperature is only 120°C, which is not high. Summary of the invention

[0004] In order to extend the service life of a two-component polyurethane potting adhesive in a high temperature and high humidity environment, the first aspect of the present invention provides an aging-resistant two-component polyurethane potting adhesive, comprising a curing agent as component A and a main adhesive as component B, with a ratio range of A:B=(10-120):100, and the raw materials for preparing the main adhesive as component B include, by weight: 10-98 parts of polyol, 0-30 parts of plasticizer I, 0-30 parts of flame retardant I, 1-10 parts of epoxy group compound, 0-75 parts of filler, 0.01-0.1 parts of defoaming agent, 0.01-0.5 parts of molecular sieve, and 0.001-0.05 parts of catalyst.

[0005] As a preferred embodiment, the weight ratio of the curing agent of component A to the main adhesive of component B is (20-100):100.

[0006] As a preferred embodiment, the weight ratio of the curing agent of component A to the main adhesive of component B is 20:100.

[0007] As a preferred embodiment, the raw materials for preparing the B component main rubber include, by weight: 60-80 parts of polyol, 16-20 parts of plasticizer I, 0-20 parts of flame retardant I, 1-5 parts of epoxy group compound, 0-60 parts of filler, 0.001-0.003 parts of defoaming agent, 0.1-0.3 parts of molecular sieve, and 0.003-0.005 parts of catalyst.

[0008] As a preferred embodiment, the raw materials for preparing the B component main glue include, by weight: 80 parts of polyol, 16 parts of plasticizer I, 10 parts of flame retardant I, 4 parts of epoxy group compound, 0.001 parts of defoaming agent, 0.2 parts of molecular sieve, and 0.005 parts of catalyst.

[0009] As a preferred embodiment, the raw materials for preparing the B component main glue include, by weight: 40 parts of polyol, 16 parts of plasticizer I, 0 parts of flame retardant I, 4 parts of epoxy group compound, 0.001 parts of defoaming agent, 0.2 parts of molecular sieve, 0.005 parts of catalyst, and 56 parts of filler.

[0010] As a preferred embodiment, the raw materials for preparing the curing agent of component A include isocyanate, plasticizer II, and flame retardant II.

[0011] As a preferred embodiment, the raw materials for preparing the curing agent of component A include 15-35 parts by weight of isocyanate, 1-10 parts by weight of plasticizer II, and 0-10 parts by weight of flame retardant II.

[0012] As a preferred embodiment, when the filler in the main adhesive of component B is 0 parts by weight, the raw materials for preparing the curing agent of component A include 30 parts by weight of isocyanate, 10 parts of plasticizer II, and 10 parts of flame retardant.

[0013] As a preferred embodiment, when the main adhesive of component B contains fillers, the raw materials for preparing the curing agent of component A include 10 parts of polymerized MDI, 7 parts of liquefied MDI, and 3 parts of plasticizer II in parts by weight.

[0014] As a preferred embodiment, the isocyanate is liquefied MDI, diphenylmethane diisocyanate; the plasticizer II is DOTP (dioctyl terephthalate); the flame retardant I and flame retardant II are both phosphorus-based flame retardants, preferably, the flame retardant I and flame retardant II are both tricresyl phosphate.

[0015] As a preferred embodiment, the polyol is selected from at least one of castor oil polyol, modified castor oil polyol, modified palm oil polyol, modified cashew nut shell oil polyol, modified soybean oil polyol, polyether polyol, 1,4-butanediol, dipropylene glycol, ethylene glycol, and 2-ethyl-1,3-hexanediol.

[0016] As a preferred embodiment, when the filler in the main rubber of component B is 0 parts by weight, the polyol is castor oil polyol.

[0017] As a preferred embodiment, when the main rubber of component B contains fillers, the polyol is castor oil polyol and modified castor oil polyol, and the weight ratio of the castor oil polyol and the modified castor oil polyol is (35-40): (0-5).

[0018] As a preferred embodiment, the plasticizer I and the plasticizer II are both selected from at least one of dioctyl terephthalate, dimethyl phthalate, diethyl phthalate, di-n-butyl phthalate, dioctyl phthalate, butyl benzyl phthalate, di(2-ethyl)hexyl phthalate, diisononyl phthalate, dioctyl adipate, epoxy soybean oil, and diisooctyl cyclohexanedicarboxylate.

[0019] As a preferred embodiment, the plasticizer I is dioctyl terephthalate.

[0020] As a preferred embodiment, the epoxy group compound is a multifunctional epoxy diluent with a functionality ≥ 3 or a low-viscosity epoxy resin, and the viscosity of the low-viscosity epoxy resin at 25° C. is 10000-16000 mPa·s.

[0021] As a preferred embodiment, the multifunctional epoxy diluent with a functionality ≥ 3 is trimethylolpropane triglycidyl ether.

[0022] As a preferred embodiment, the epoxy equivalent of the low-viscosity epoxy resin is 180-200 g / mol.

[0023] As a preferred embodiment, the epoxy equivalent of the low-viscosity epoxy resin is 184-195 g / mol.

[0024] As a preferred implementation, the model of the low-viscosity epoxy resin is E51.

[0025] The applicant found in the experiment that the use of low molecular weight, low viscosity multi-functional epoxy group compounds can obtain polyurethane potting glue with moderate viscosity and hardness, and good anti-aging performance. The possible reason is speculated that: adding low molecular weight, low viscosity multi-functional epoxy group compounds to the polyurethane glue formula is in a free state at the beginning of the reaction and does not participate in the curing reaction. The formed polyurethane potting glue has a certain toughness and softness. These multi-functional epoxy group compounds can react with the decomposition products after aging during the use of the polyurethane potting glue, thereby maintaining the use state of the polyurethane glue and extending the service life of the polyurethane potting glue.

[0026] The applicant further discovered that polyurethane sealant formed by using low-viscosity epoxy resin has better sealing effect, while using low-functionality epoxy diluent in high temperature and high humidity environment will cause the polyurethane sealant to liquefy quickly and lose hardness quickly.

[0027] The inventors further found that the use of 5A low-alkalinity molecular sieves in combination with multifunctional epoxy compounds can achieve better aging resistance. Adding 5A low-alkalinity molecular sieves can reduce the water content of the colloid and can synergistically improve the aging resistance with multifunctional epoxy compounds.

[0028] As a preferred embodiment, the molecular sieve is selected from one of type 3A molecular sieve, type 4A molecular sieve and type 5A molecular sieve.

[0029] As a preferred embodiment, the molecular sieve is a 5A type molecular sieve, which is a low-alkalinity molecular sieve with a pH of 8-9 and is purchased from Luoyang Jianlong Micro-Nano New Materials Co., Ltd.

[0030] As a preferred embodiment, the molecular sieve is a 5A type molecular sieve.

[0031] As a preferred embodiment, the filler is selected from at least one of aluminum hydroxide, aluminum oxide, carbon black, silicon dioxide, and calcium carbonate.

[0032] As a preferred embodiment, the filler is aluminum hydroxide.

[0033] As a preferred embodiment, the particle size of the aluminum hydroxide is 1-25 μm.

[0034] As a preferred embodiment, the particle size of the aluminum hydroxide is a combination of 1 μm and 25 μm.

[0035] As a preferred embodiment, the weight ratio of the 1 μm and 25 μm aluminum hydroxide is (10-30): (30-40).

[0036] As a preferred embodiment, the weight ratio of the 1 μm and 25 μm aluminum hydroxide is 20:36.

[0037] As a preferred embodiment, the catalyst is a tin catalyst.

[0038] As a preferred embodiment, the tin catalyst includes but is not limited to dibutyltin dilaurate, stannous octoate, dibutyltin diacetate, and dibutyltin didodecylsulfide.

[0039] The second aspect of the present invention provides a method for preparing an aging-resistant two-component polyurethane potting adhesive, comprising the following steps:

[0040] S1: prepare curing agent of component A: stir and heat plasticizer II and flame retardant II to 100-120°C, remove water in vacuum, cool to below 60°C, add isocyanate, stir evenly and set aside;

[0041] S2 Preparation of component B main adhesive: Stir and heat polyol, plasticizer I, filler, epoxy group compound, flame retardant I to 100-120°C, remove water in vacuum, cool to 60°C, add molecular sieve, defoamer and catalyst, stir evenly and set aside;

[0042] S3: Mix the curing agent of component A and the main adhesive of component B and then use them.

[0043] Compared with the prior art, the present invention has the following beneficial effects:

[0044] (1) The aging-resistant two-component polyurethane potting adhesive of the present invention is different from the epoxy / polyurethane interpenetrating network structure. In the present invention, a multifunctional epoxy diluent or a low-viscosity epoxy resin is directly added to the polyurethane adhesive formula, and no epoxy curing agent is added. The prepared polyurethane potting adhesive has excellent aging resistance under high temperature and high humidity environment.

[0045] (2) The aging-resistant two-component polyurethane potting adhesive of the present invention can obtain a polyurethane potting adhesive with moderate viscosity and hardness by using a multifunctional epoxy diluent or a low-viscosity epoxy resin, and has good aging-resistant performance.

[0046] (3) The aging-resistant two-component polyurethane potting glue of the present invention uses low-viscosity epoxy resin at a lower addition amount to form a polyurethane glue with better sealing effect, and is suitable for preparing a potting glue.

[0047] (4) The aging-resistant two-component polyurethane potting adhesive of the present invention has good sealing effect whether prepared with or without adding fillers, and the multifunctional epoxy diluent, low-viscosity epoxy resin and molecular sieve work synergistically to achieve better effect and extend service life. DETAILED DESCRIPTION

[0048] Embodiment 1

[0049] An aging-resistant two-component polyurethane potting adhesive comprises a component A curing agent and a component B main adhesive, wherein the weight ratio of the component A curing agent to the component B main adhesive is 50:100.

[0050] When the main adhesive of component B does not contain filler, the raw materials for preparing the curing agent of component A include 30 parts of isocyanate, 10 parts of plasticizer II, and 10 parts of flame retardant II in parts by weight.

[0051] The isocyanate is liquefied MDI purchased from Wanhua Chemical, model number MDI-100LL; the plasticizer II is DOTP (dioctyl terephthalate); and the flame retardant II is tricresyl phosphate.

[0052] The raw materials for preparing the main rubber of component B are shown in the following Table 1 in parts by weight:

[0053] Table 1

[0054]

[0055]

[0056] The epoxy resin E51 was purchased from Jiangmen Sanmu Chemical Industry, with a brand of 128 epoxy resin, a viscosity of 10000-16000 mPa·s at 25° C., and an epoxy equivalent of 184-195 g / mol;

[0057] The castor oil is refined first-grade commercially available castor oil.

[0058] The defoamer was purchased from BYK, with the brand name BYK-2735;

[0059] The 5A low alkalinity molecular sieve has a pH of 8-9 and is purchased from Luoyang Jianlong Micro-Nano New Materials Co., Ltd.

[0060] The catalyst is dibutyltin dilaurate.

[0061] A method for preparing an aging-resistant two-component polyurethane potting adhesive comprises the following steps:

[0062] S1: Prepare curing agent of component A: Stir and heat plasticizer and flame retardant to 110°C, remove water under vacuum, cool to below 60°C, add isocyanate, stir evenly and set aside;

[0063] S2 Preparation of component B main glue: polyol, plasticizer, epoxy group compound, stir and heat to 110°C, remove water in vacuum, cool to 60°C, add molecular sieve, defoamer and catalyst, stir evenly and set aside;

[0064] S3: Mix the curing agent of component A and the main adhesive of component B and then use them.

[0065] Embodiment 2

[0066] The invention discloses an aging-resistant two-component polyurethane potting adhesive. The preparation raw materials include a component A curing agent and a component B main adhesive. The weight ratio of the component A curing agent to the component B main adhesive is 20:100.

[0067] When the main adhesive of component B contains fillers, the raw materials for preparing the curing agent of component A include 10 parts of polymerized MDI, 7 parts of liquefied MDI and 3 parts of plasticizer II in parts by weight.

[0068] The polymeric MDI was purchased from Wanhua Chemical with a model number of PM200; the liquefied MDI was purchased from Wanhua Chemical with a model number of MDI-100LL; and the plasticizer II was DOTP (dioctyl terephthalate).

[0069] The raw materials for preparing the main adhesive of component B are shown in Table 2 below in parts by weight:

[0070] Table 2

[0071]

[0072]

[0073] The epoxy resin E51 was purchased from Jiangmen Sanmu Chemical Industry, with a brand of 128 epoxy resin, a viscosity of 10000-16000 mPa·s at 25° C., and an epoxy equivalent of 184-195 g / mol;

[0074] The castor oil is refined first-grade commercially available castor oil.

[0075] The modified castor oil was purchased from Shanghai Jingri New Material Technology Co., Ltd. with a brand name of A30.

[0076] The defoamer was purchased from BYK, with the brand name BYK-2735;

[0077] The 5A low alkalinity molecular sieve has a pH of 8-9 and is purchased from Luoyang Jianlong Micro-Nano New Materials Co., Ltd.

[0078] The catalyst is dibutyltin dilaurate.

[0079] The particle size of the aluminum hydroxide is a combination of 1 μm and 25 μm, and the weight ratio of the 1 μm and 25 μm aluminum hydroxide is 20:36.

[0080] A method for preparing an aging-resistant two-component polyurethane potting adhesive comprises the following steps:

[0081] S1: Prepare curing agent of component A: heat the plasticizer to 110°C with stirring, remove water under vacuum, cool to below 60°C, add polymerized isocyanate, liquefy isocyanate, stir evenly and set aside;

[0082] S2 Preparation of component B main glue: polyol, plasticizer, filler, epoxy group compound, stir and heat to 110°C, remove water in vacuum, cool to 60°C, add molecular sieve, defoamer and catalyst, stir evenly and set aside;

[0083] S3: Mix the curing agent of component A and the main adhesive of component B and then use them.

[0084] Performance Testing

[0085] The polyurethane potting adhesive of Example 1 and Example 2 was placed in a mold with a thickness of 10 mm and a diameter of 50 mm, cured at room temperature of 25°C, and then placed under saturated water vapor pressure of 143°C, observed every two hours, and its Shore hardness and surface liquefaction degree were recorded. The test results are shown in Tables 3 and 4.

[0086] The Shore hardness is measured using a Shore durometer.

[0087] Table 3

[0088] initial 8h 10h 12h 14h 16h Example 1 41A 22A 16A Sticky surface Surface liquefaction All liquefied Example 2 41A 23A 21A 14A Surface liquefaction All liquefied Comparative Example 1 42A 18A Sticky surface Surface liquefaction All liquefied / Comparative Example 2 41A Surface liquefaction All liquefied / / / Comparative Example 3 41A Surface liquefaction All liquefied / / / Comparative Example 4 41A Surface liquefaction All liquefied / / /

[0089] Table 4

[0090] Aging performance initial 10h 20h 34h 36h Example 3 45D 31D 28D 23D 21D Example 4 45D 37D 35D 30D 29D Comparative Example 5 45D 34D 26D 12D 12D Comparative Example 6 45D 26D 22D 11D 11D Comparative Example 7 45D 31D 25D 11D 11D

[0091] “ / ” in the table means that after all liquefaction, no further testing is required.

Claims

1. An aging-resistant two-component polyurethane potting adhesive, characterized in that: The invention comprises a curing agent as component A and a main adhesive as component B, wherein the ratio range is A:B=(10-120):100, and the raw materials for preparing the main adhesive as component B include, by weight, 10-98 parts of polyol, 0-30 parts of plasticizer I, 0-30 parts of flame retardant I, 1-10 parts of epoxy group compound, 0-75 parts of filler, 0.01-0.1 parts of defoamer, 0.01-0.5 parts of molecular sieve and 0.001-0.05 parts of catalyst.

2. The aging-resistant two-component polyurethane potting adhesive according to claim 1, characterized in that: The raw materials for preparing the A component curing agent include isocyanate, plasticizer II and flame retardant II.

3. The aging-resistant two-component polyurethane potting adhesive according to claim 1, characterized in that: The polyol is selected from at least one of castor oil polyol, modified castor oil polyol, modified palm oil polyol, modified cashew nut shell oil polyol, modified soybean oil polyol, polyether polyol, 1,4-butanediol, dipropylene glycol, ethylene glycol, and 2-ethyl-1,3-hexanediol.

4. The aging-resistant two-component polyurethane potting adhesive according to claim 3, characterized in that: The plasticizer I and plasticizer II are both selected from at least one of dioctyl terephthalate, dimethyl phthalate, diethyl phthalate, di-n-butyl phthalate, dioctyl phthalate, butyl benzyl phthalate, di(2-ethyl)hexyl phthalate, diisononyl phthalate, dioctyl adipate, epoxy soybean oil, and diisooctyl cyclohexanedicarboxylate.

5. The aging-resistant two-component polyurethane potting adhesive according to claim 1, characterized in that: The epoxy group compound is a multifunctional epoxy diluent with a functionality of ≥3 or a low-viscosity epoxy resin, and the low-viscosity epoxy resin has a viscosity of 10000-16000 mPa·s at 25°C.

6. The aging-resistant two-component polyurethane potting adhesive according to claim 5, characterized in that: The epoxy equivalent of the low-viscosity epoxy resin is 180-200 g / mol.

7. The aging-resistant two-component polyurethane potting adhesive according to claim 1, characterized in that: The molecular sieve is selected from one of type 3A molecular sieve, type 4A molecular sieve and type 5A molecular sieve.

8. The aging-resistant two-component polyurethane potting adhesive according to claim 2, characterized in that: The filler is selected from at least one of aluminum hydroxide, aluminum oxide, carbon black, silicon dioxide and calcium carbonate.

9. The aging-resistant two-component polyurethane potting adhesive according to claim 8, characterized in that: The particle size of the aluminum hydroxide is 1-25 μm.

10. A method for preparing the aging-resistant two-component polyurethane potting adhesive according to any one of claims 3 to 9, characterized in that: The following steps are involved: S1: prepare curing agent of component A: stir and heat plasticizer II and flame retardant II to 100-120°C, remove water in vacuum, cool to below 60°C, add isocyanate, stir evenly and set aside; S2 Preparation of component B main adhesive: Stir and heat polyol, plasticizer I, filler, epoxy group compound, flame retardant I to 100-120°C, remove water in vacuum, cool to 60°C, add molecular sieve, defoamer and catalyst, stir evenly and set aside; S3: Mix the curing agent of component A and the main adhesive of component B in proportion and then use.

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