Solid unsaturated polyester resin for prepreg and preparation method thereof

Abstract

The invention provides solid unsaturated polyester resin for prepreg. The solid unsaturated polyester resin comprises the following components in percentage by weight: a first group: 25-40% of isophthalic acid, 5-10% of neopentyl glycol, 10-20% of methylpropanediol, 3-10% of ethylene glycol, 2-3% of trimethylolpropane and 0.03% of a catalyst; the second group comprises 15-30% of maleic anhydride, 5-10% of propylene glycol and 0.03% of a polymerization inhibitor; 8 to 10 percent of diallyl phthalate; the sum of the weight percentages of the components is 100%. The solid unsaturated polyester resin for the prepreg provided by the invention is in a solid state at normal temperature, has a softening point of about 60 DEG C, is free of organic matters volatilized at normal temperature, is environment-friendly, can be thermally cured, is applied to the prepreg or powder coating of the unsaturated polyester resin, and has good fluidity and good wettability to glass fibers at the temperature of thermally curing; the prepreg and the molded product with high glass fiber content can be obtained, and the performance is excellent.

Description

Technical Field

[0001] The invention belongs to the field of unsaturated polyester resins, and in particular relates to a solid unsaturated polyester resin for prepreg and a preparation method thereof. Background Art

[0002] General-purpose unsaturated polyester resin is usually a liquid with fluidity at room temperature, which is composed of high-molecular polyester containing double bonds dissolved in styrene. It is a thermosetting resin and is mainly used in products such as fiberglass, artificial stone, handicrafts, and coatings. Unsaturated polyester resin has good operability and can meet the performance requirements of most products, so it is widely used in various industries.

[0003] Conventional SMC (molding material) is a sheet molding material made of unsaturated polyester resin and glass fiber filler, which can be molded. This material has good molding process and is widely used. However, the glass fiber content of this material is low, generally around 28%, so the strength of the product is not high, and the sheet contains a large amount of volatile organic matter styrene. Therefore, in order to increase the glass fiber content and reduce volatile organic matter, another prepreg process must be adopted to reduce the filler content and increase the glass fiber cloth content up to 55%. This puts forward different requirements for the resin, requiring the physical state of the resin to be solid at room temperature, with a high softening point and no room temperature volatility. Summary of the invention

[0004] An object of the present invention is to provide a solid unsaturated polyester resin for prepreg which is solid at room temperature, has a high softening point and does not volatilize at room temperature in view of the above technical problems to be solved.

[0005] Another object of the present invention is to provide a method for preparing the solid unsaturated polyester resin for prepreg.

[0006] In order to achieve the following objectives, the present invention provides a solid unsaturated polyester resin for prepreg, which comprises the following components by weight:

[0007] Group 1: isophthalic acid 25-40%, neopentyl glycol 5-10%, methyl propylene glycol 10-20%, ethylene glycol 3-10%, trimethylolpropane 2-3%, catalyst monobutyl tin oxide 0.03%;

[0008] The second group: maleic anhydride 15-30%, propylene glycol 5-10%, inhibitor 0.03%; diallyl phthalate 8-10%;

[0009] The sum of the weight percentages of the above components is 100%.

[0010] Preferably, the solid unsaturated polyester resin for prepreg of the present invention comprises the following components by weight:

[0011] Group 1: isophthalic acid 28-39%, neopentyl glycol 9%, methyl propylene glycol 11-16%, ethylene glycol 4-9%, trimethylolpropane 2%, catalyst 0.03%;

[0012] The second group: maleic anhydride 16-24%, propylene glycol 5-7%, inhibitor 0.03%; diallyl phthalate 9-10%;

[0013] The sum of the weight percentages of the above components is 100%.

[0014] Preferably, the catalyst is monobutyltin oxide.

[0015] Preferably, the polymerization inhibitor is hydroquinone.

[0016] On the other hand, the present invention also provides a method for preparing the solid unsaturated polyester resin for prepreg, which comprises the following steps:

[0017] (1) Add the first group of methylpropanediol, ethylene glycol and catalyst into a reaction pot according to the formula, stir evenly, and then add the first group of isophthalic acid, neopentyl glycol and trimethylolpropane under stirring.

[0018] (2) After the materials are added, nitrogen is supplied at a flow rate of 2 cubic meters per hour, and water is supplied to the horizontal condenser to increase the temperature. The distillation temperature is controlled to be no more than 103°C, and the maximum temperature of the material is no more than 215°C. When the sampled material is transparent and the acid value is less than 5 mgKOH / g, the reactor is stopped from heating and cooled;

[0019] (3) When the material temperature drops to 180°C, add the second group of propylene glycol and the polymerization inhibitor hydroquinone, and then add the second group of maleic anhydride; after adding the materials, increase the temperature, control the distillation temperature not to exceed 102°C, and the maximum material temperature not to exceed 205°C. When the distillation temperature is lower than 90°C, increase the nitrogen volume to 10 cubic meters / hour and react at a constant temperature;

[0020] (4) When the temperature is kept constant until the acid value is 28-30 mgKOH / g and the polyester viscosity is 60-80P / 120°C, the temperature is lowered to control the polyester viscosity;

[0021] (5) When the material temperature drops to 150° C., diallyl phthalate is added to dissolve the material, and the material is unloaded and packaged at 100° C. to obtain the solid unsaturated polyester resin for prepreg.

[0022] The solid unsaturated polyester resin for prepreg with a high softening point provided by the present invention is in a solid state at room temperature, has a softening point of about 60°C, contains no organic matter volatile at room temperature, is environmentally friendly, can be thermally cured, can be applied to prepreg or powder coating of unsaturated polyester resin, has good fluidity at the temperature for thermal curing, has good wettability to glass fiber, can achieve prepreg and molded products with high glass fiber content, have excellent performance, have obvious cost advantages compared with epoxy resin prepreg and powder coating, and have very broad application prospects. DETAILED DESCRIPTION

[0023] The present invention is further described in detail below in conjunction with specific examples. It should be understood that the following examples are only used to illustrate and explain the present invention, and are not intended to constitute any limitation on the scope of the present invention.

[0024] Example 1

[0025] The reactant formula in the reactor is as follows:

[0026] Group 1: 650g isophthalic acid, 150g neopentyl glycol, 180g methylpropylene glycol, 155g ethylene glycol, 40g trimethylolpropane, 0.5g monobutyltin oxide catalyst;

[0027] The second group: maleic anhydride 275g, propylene glycol 76g, polymerization inhibitor hydroquinone 0.5g, diallyl phthalate 150g.

[0028] The preparation steps of solid unsaturated polyester resin for prepreg are as follows:

[0029] 1. Check whether the equipment, electrical appliances, instruments, valves and Grade A raw materials are normal.

[0030] 2. According to the above formula, add the first group of methylpropanediol, ethylene glycol and catalyst monobutyltin oxide into the reaction pot respectively, stir evenly, and then add the first group of isophthalic acid, neopentyl glycol and trimethylolpropane under stirring.

[0031] 3. After the materials are added, nitrogen is supplied to the reactor (flow rate is 2 cubic meters / hour), water is supplied to the horizontal condenser, and the temperature is rapidly increased. The distillation temperature is controlled at no more than 103°C, and the maximum material temperature does not exceed 215°C. When the sampled material is transparent and the acid value is less than 5mgKOH / g, the reactor stops heating and cooling.

[0032] 4. When the material temperature drops to 180°C, add the second group of propylene glycol and inhibitor hydroquinone, and then add the second group of maleic anhydride; after adding the materials, increase the temperature and control the distillation temperature not to exceed 102°C. The maximum temperature of the material does not exceed 205°C. When the distillation temperature is lower than 90°C, increase the nitrogen volume to 10 cubic meters / hour and react at a constant temperature.

[0033] 5. When the constant temperature reaction reaches the acid value of 28-30 mgKOH / g and the polyester viscosity of 60-80P / 120°C, the control of the polyester viscosity is regarded as the end point and the reactor begins to cool down.

[0034] 6. When the material temperature drops to 150°C, add diallyl phthalate to dissolve. When the material is at 100°C, unload and package to obtain solid unsaturated polyester resin for prepreg.

[0035] Through observation and detection, the obtained solid unsaturated polyester resin for prepreg is in solid state at room temperature, has a softening point higher than 60°C, and is non-volatile at room temperature.

[0036] Example 2

[0037] The reactant formula in the reactor is as follows:

[0038] Group 1: 452g isophthalic acid, 150g neopentyl glycol, 270g methyl propanediol, 62g ethylene glycol, 40g trimethylolpropane, 0.5g monobutyl tin oxide catalyst;

[0039] The second group: maleic anhydride 392g, propylene glycol 114g, inhibitor hydroquinone 0.5g, diallyl phthalate 160g.

[0040] The preparation steps of solid unsaturated polyester resin for prepreg are as follows:

[0041] 1. Check whether the equipment, electrical appliances, instruments, valves and Grade A raw materials are normal.

[0042] 2. Add the first group of methylpropanediol, ethylene glycol and catalyst monobutyl tin oxide into the reaction pot according to the formula, stir evenly, and then add the first group of isophthalic acid, neopentyl glycol and trimethylolpropane under stirring.

[0043] 3. After the materials are added, nitrogen is supplied to the reactor (flow rate is 2 cubic meters / hour), water is supplied to the horizontal condenser, and the temperature is raised rapidly. The distillation temperature is controlled at no more than 103°C, and the maximum material temperature does not exceed 215°C. When the sampled material is transparent and the acid value is less than 5mgKOH / g, the reactor stops heating and cooling.

[0044] 4. When the material temperature drops to 180°C, add the second group of propylene glycol and inhibitor hydroquinone, and then add the second group of maleic anhydride; after adding the materials, quickly raise the temperature, control the distillation temperature not to exceed 102°C, and the maximum temperature of the material does not exceed 205°C. When the distillation temperature is lower than 90°C, increase the nitrogen volume to 10 cubic meters / hour and react at a constant temperature.

[0045] 5. Keep the reaction temperature constant until the acid value reaches 28-30 mgKOH / g and the polyester viscosity reaches 50-60P / 120℃. The control of the polyester viscosity is regarded as the end point and the reactor begins to cool down.

[0046] 6. When the material temperature drops to 150°C, add diallyl phthalate to dissolve. When the material is at 100°C, unload and package to obtain solid unsaturated polyester resin for prepreg.

[0047] Through observation and detection, the obtained solid unsaturated polyester resin for prepreg is in solid state at room temperature, has a softening point higher than 60°C, and does not volatilize at room temperature.

[0048] Product performance test

[0049] Prepreg preparation:

[0050] The solid unsaturated polyester resin for prepreg of Example 1-2 was mixed with ammonium polyphosphate, benzoyl peroxide and tert-butyl perbenzoate in a weight ratio of 100:35:0.5:2, stirred evenly at 90°C, and heated at 600 g / m 2 The prepreg is evenly coated on the glass fiber cloth, placed between two layers of film, and then rolled into a sheet and cooled to room temperature to obtain a prepreg.

[0051] Molding process: Place the above prepreg in a mold, cure at 150°C for 2.5 minutes, and test the properties of the molded product. The test results are shown in Table 1 below. The control product is a common commercially available general-purpose SMC (Guangdong Baihuida New Materials Co., Ltd., product model BHD-482-01GY).

[0052] Table 1: Comparison of performance data of molded products and general SMC performance data

[0053] Inspection items Test Method Example 1 Example 2 Commercially available general-purpose SMC Glass fiber content (%) GB / T 2577-2005 40 41 29 Tensile strength(MPa) GB / T 1447-2005 160 150 73 <![CDATA[Tensile elastic modulus (*10 4 MPa)]]> GB / T 1447-2005 2.5 2.4 1.1 Bending strength(MPa) GB / T 1449-2005 301 310 170 <![CDATA[Flexural modulus of elasticity (*10 4 MPa)]]> GB / T 1449-2005 2.7 2.8 1.2 <![CDATA[Impact toughness (kJ / m 2 )]]> GB / T 1043.1-2008 170 180 71

[0054] It can be seen from the data in Table 1 above that the prepreg and its molded product made by using the solid unsaturated polyester resin for prepreg of the present invention have high tensile strength, flexural strength and impact toughness, and the comprehensive performance is greatly improved compared with the general SMC material, and can be used under application conditions with higher requirements.

Claims

1. A solid unsaturated polyester resin for prepreg, characterized in that The following components are included by weight: Group 1: isophthalic acid 25-40%, neopentyl glycol 5-10%, methyl propylene glycol 10-20%, ethylene glycol 3-10%, trimethylolpropane 2-3%, catalyst 0.03%; The second group: maleic anhydride 15-30%, propylene glycol 5-10%, inhibitor 0.03%; diallyl phthalate 8-10%; The sum of the weight percentages of the above components is 100%.

2. The solid unsaturated polyester resin for prepreg according to claim 1, characterized in that The solid unsaturated polyester resin for prepreg is characterized by comprising the following components by weight: Group 1: isophthalic acid 28-39%, neopentyl glycol 9%, methyl propylene glycol 11-16%, ethylene glycol 4-9%, trimethylolpropane 2%, catalyst 0.03%; The second group: maleic anhydride 16-24%, propylene glycol 5-7%, inhibitor 0.03%; diallyl phthalate 9-10%; The sum of the weight percentages of the above components is 100%.

3. The solid unsaturated polyester resin for prepreg according to claim 1 or 2, characterized in that: The catalyst is monobutyltin oxide.

4. The solid unsaturated polyester resin for prepreg according to claim 1 or 2, characterized in that: The polymerization inhibitor is hydroquinone.

5. A method for preparing a solid unsaturated polyester resin for prepreg according to any one of claims 1 to 4, characterized in that The following steps are involved: (1) adding methyl propylene glycol, ethylene glycol and a catalyst of the first group, stirring them evenly, and then adding isophthalic acid, neopentyl glycol and trimethylolpropane of the first group under stirring; (2) After the materials are added, nitrogen is supplied at a flow rate of 2 cubic meters per hour, and water is supplied to the horizontal condenser to increase the temperature. The distillation temperature is controlled to be no more than 103°C, and the maximum temperature of the material is no more than 215°C. When the sampled material is transparent and the acid value is less than 5 mgKOH / g, the heating is stopped and the temperature is lowered; (3) When the material temperature drops to 180°C, add the second group of propylene glycol and polymerization inhibitor, then add the second group of maleic anhydride, and then increase the temperature. The distillation temperature is controlled not to exceed 102°C, and the maximum temperature of the material does not exceed 205°C. When the distillation temperature is lower than 90°C, increase the nitrogen volume to 10 cubic meters / hour and react at a constant temperature; (4) When the temperature is kept constant until the acid value is 28-30 mgKOH / g and the polyester viscosity is 60-80P / 120°C, the temperature is lowered to control the polyester viscosity; (5) When the material temperature drops to 150°C, add diallyl phthalate to dissolve it, and then unload and package it at 100°C.