1. The unsaturated polyester resin is characterized by comprising the following raw materials in parts by weight: 226 portions of neopentyl glycol 196-.

2. The unsaturated polyester resin according to claim 1, comprising the following raw materials in parts by weight: 208 portions of neopentyl glycol 204-.

3. A method for preparing unsaturated polyester resin is characterized by comprising the following steps:

s1, adding materials in the first step: adding 196-226 parts of neopentyl glycol, 130-150 parts of monoethylene glycol and 68-74 parts of phthalic anhydride into a reaction kettle in N₂Heating in atmosphere, stirring after the materials in the reaction kettle are completely melted to slowly raise the temperature to 160-The acid value at the end of the polymerization reaction reaches the standard;

s2, adding materials in the second step: when the acid value of the material in the S1 reaches the standard, cooling the reaction kettle to 160-170 ℃, keeping the temperature for a period of time, adding 26-30 parts of dipropylene glycol and 270-280 parts of maleic anhydride, continuing to heat to 200-215 ℃ by a 'step gradient heating method', keeping the temperature for a period of time at each step, and controlling the overall reaction time until the end point of the polycondensation reaction, the acid value and the viscosity of the polyester reach the standard;

s3, when the acid value of the material in the S2 and the viscosity of the polyester reach the standards, cooling to 160-170 ℃, adding the reactant into a container containing 320-340 parts of styrene solution, uniformly stirring, and slowly cooling to normal temperature to obtain the unsaturated polyester resin.

4. The method of claim 2, wherein in the step of S1 or S2: the constant temperature time of each stage of the stage gradient heating method is 50-75 min.

5. The method for preparing unsaturated polyester resin according to claim 2, wherein in the step of S1: the integral reaction time is 5-8h, and the material acid value standard is 20-25 mgKOH/g.

6. The method for preparing unsaturated polyester resin according to claim 2, wherein in the step of S2: the heat preservation time at 170 ℃ of 160-.

Background

The unsaturated polyester resin is one of thermosetting resins, is widely applied to various composite materials such as buildings, anticorrosion materials, automobiles, electronic and electric appliances and the like, has simple and convenient production process, can be cured at normal temperature and normal pressure, and has the process performance characteristics of outstanding weather resistance and oil resistance, high hardness, good gloss, excellent electrical property and the like. However, the existing general unsaturated polyester resin has the problems of insufficient water resistance and corrosion resistance, large shrinkage rate, low strength and the like after being cured, and can not meet the requirements of practical application.

Disclosure of Invention

In order to solve the problems, the invention utilizes neopentyl glycol to replace the traditional propylene glycol, improves the water resistance and the corrosion resistance of the finished unsaturated polyester resin, and enables the cured body of the unsaturated polyester resin to have good mechanical strength by compounding with a small amount of high-performance dipropylene glycol, and discloses the unsaturated polyester resin which is characterized by comprising the following raw materials in parts by weight: 226 portions of neopentyl glycol 196-.

A method for preparing unsaturated polyester resin is characterized by comprising the following steps:

s1, adding materials in the first step: adding 196-226 parts of neopentyl glycol, 130-150 parts of monoethylene glycol and 68-74 parts of phthalic anhydride into a reaction kettle in N₂Heating in the atmosphere, starting stirring after materials in the reaction kettle are completely melted, slowly raising the temperature to 160-;

s2, adding materials in the second step: when the acid value of the material in the S1 reaches the standard, cooling the reaction kettle to 160-170 ℃, keeping the temperature for a period of time, adding 26-30 parts of dipropylene glycol and 270-280 parts of maleic anhydride, continuing to heat to 200-215 ℃ by a 'step gradient heating method', keeping the temperature for a period of time at each step, and controlling the overall reaction time until the end point of the polycondensation reaction, the acid value and the viscosity of the polyester reach the standard;

s3, when the acid value of the material in the S2 and the viscosity of the polyester reach the standards, cooling to 160-170 ℃, adding the reactant into a container containing 320-340 parts of styrene solution, uniformly stirring, and slowly cooling to normal temperature to obtain the unsaturated polyester resin.

Preferably, in the step of S1 or S2: the constant temperature time of each stage of the stage gradient heating method is 50-75 min.

Preferably, in the step S1: the integral reaction time is 5-8h, and the material acid value standard is 20-25 mgKOH/g.

Preferably, in the step S2: the heat preservation time at 170 ℃ of 160-.

The invention has the beneficial effects that:

1. at present, the price of the corrosion-resistant unsaturated resin is higher, the price of the unsaturated polyester resin prepared from neopentyl glycol is low, the water resistance and the corrosion resistance of a cured body of the unsaturated polyester resin are far superior to those of common o-benzene type and m-benzene type unsaturated polyester resins, the cost performance is high, the structure of the unsaturated polyester resin can be optimized by using the neopentyl glycol, the flexibility of the resin can be improved by using the high-performance dipropylene glycol, and the mechanical properties of the cured body of the unsaturated polyester resin are improved to a certain extent by compounding the dipropylene glycol and the m-benzene type unsaturated polyester resin. Dipropylene glycol has good compatibility with low profile additives, and low profile additives such as polyvinyl acetate, polymethyl methacrylate, polystyrene, etc. can be used to significantly reduce the linear shrinkage of the cured product.

2. The gradient-stage heating method can improve the utilization rate of raw materials, ensure full reaction, effectively control the growth of molecular mass and reduce the generation of branched chain structures.

Detailed Description

Comparative examples 1 to 3 are based on the preparation process provided by the present invention: comparative example 1 was prepared using conventional propylene glycol, without neopentyl glycol and dipropylene glycol; comparative example 2 is the use of neopentyl glycol alone and no dipropylene glycol; comparative example 3 was conducted using conventional propylene glycol and high performance dipropylene glycol.

Examples 1-3 are the preparation provided by the present invention. The formula ratio of each component is shown in table 1.

Table 1:

comparative example 1:

s1, adding materials in the first step: 215 parts of propylene glycol,167 parts of monoethylene glycol and 71 parts of phthalic anhydride are added into a reaction kettle in N₂Heating in the atmosphere, starting stirring after materials in the reaction kettle are completely melted, slowly raising the temperature to 165 ℃, then raising the temperature to 195 ℃ by a 'step gradient heating method', keeping the temperature for 60min at each step, and controlling the whole reaction time for 7h until the acid value reaches 22mgKOH/g at the end point of the polycondensation reaction.

S2, adding materials in the second step: and when the acid value of the material in the S1 reaches the standard, cooling the reaction kettle to 165 ℃, keeping the temperature for 1.2h, adding 275 parts of maleic anhydride, continuing to heat to 207 ℃ by a 'step gradient heating method', keeping the temperature of each step for 60min, and controlling the overall reaction time to 9h until the end point of the polycondensation reaction, wherein the acid value reaches 30mgKOH/g, and the viscosity of the polyester reaches 700 mPa.s.

And S3, cooling to 165 ℃ after the acid value of the material in the S2 and the viscosity of the polyester reach standards, adding the reactant into a container containing 330 parts of styrene solution, uniformly stirring, slowly cooling to normal temperature to obtain an unsaturated polyester resin solution, and marking as a product A.

Comparative example 2:

s1, adding materials in the first step: 215 parts of neopentyl glycol, 167 parts of monoethylene glycol and 71 parts of phthalic anhydride are added into a reaction kettle, and the mixture is stirred at the temperature of N₂Heating in the atmosphere, starting stirring after materials in the reaction kettle are completely melted, slowly raising the temperature to 165 ℃, then raising the temperature to 195 ℃ by a 'step gradient heating method', keeping the temperature for 60min at each step, and controlling the whole reaction time for 7h until the acid value reaches 22mgKOH/g at the end point of the polycondensation reaction.

S2, adding materials in the second step: and when the acid value of the material in the S1 reaches the standard, cooling the reaction kettle to 165 ℃, keeping the temperature for 1.2h, adding 275 parts of maleic anhydride, continuing to heat to 207 ℃ by a 'step gradient heating method', keeping the temperature of each step for 60min, and controlling the overall reaction time to 9h until the end point of the polycondensation reaction, wherein the acid value reaches 30mgKOH/g, and the viscosity of the polyester reaches 700 mPa.s.

And S3, cooling to 165 ℃ after the acid value of the material in the S2 and the viscosity of the polyester reach standards, adding the reactant into a container containing 330 parts of styrene solution, uniformly stirring, slowly cooling to normal temperature to obtain an unsaturated polyester resin solution, and marking as a product B.

Comparative example 3:

s1, adding materials in the first step: 215 parts of propylene glycol, 140 parts of monoethylene glycol and 71 parts of phthalic anhydride are added into a reaction kettle in N₂Heating in the atmosphere, starting stirring after materials in the reaction kettle are completely melted, slowly raising the temperature to 165 ℃, then raising the temperature to 195 ℃ by a 'step gradient heating method', keeping the temperature for 60min at each step, and controlling the whole reaction time for 7h until the acid value reaches 22mgKOH/g at the end point of the polycondensation reaction.

S2, adding materials in the second step: and when the acid value of the material in the S1 reaches the standard, cooling the reaction kettle to 165 ℃, keeping the temperature for 1.2h, adding 27 parts of dipropylene glycol and 275 parts of maleic anhydride, continuing to heat to 207 ℃ by a step gradient heating method, keeping the temperature of each step constant for 60min, and controlling the overall reaction time to 9h until the end point of the polycondensation reaction, wherein the acid value reaches 30mgKOH/g, and the viscosity of the polyester reaches 700 mPa.s.

And S3, cooling to 165 ℃ after the acid value of the material in the S2 and the viscosity of the polyester reach standards, adding the reactant into a container containing 330 parts of styrene solution, uniformly stirring, slowly cooling to normal temperature to obtain an unsaturated polyester resin solution, and marking as a product C.

Example 1:

s1, adding materials in the first step: 215 parts of neopentyl glycol, 140 parts of monoethylene glycol and 71 parts of phthalic anhydride are added into a reaction kettle, and the mixture is stirred at the temperature of N₂Heating in the atmosphere, starting stirring after materials in the reaction kettle are completely melted, slowly raising the temperature to 165 ℃, then raising the temperature to 195 ℃ by a 'step gradient heating method', keeping the temperature for 60min at each step, and controlling the whole reaction time for 7h until the acid value reaches 22mgKOH/g at the end point of the polycondensation reaction.

S2, adding materials in the second step: and when the acid value of the material in the S1 reaches the standard, cooling the reaction kettle to 165 ℃, keeping the temperature for 1.2h, adding 27 parts of dipropylene glycol and 275 parts of maleic anhydride, continuing to heat to 207 ℃ by a step gradient heating method, keeping the temperature of each step constant for 60min, and controlling the overall reaction time to 9h until the end point of the polycondensation reaction, wherein the acid value reaches 30mgKOH/g, and the viscosity of the polyester reaches 700 mPa.s.

And S3, cooling to 165 ℃ after the acid value of the material in the S2 and the viscosity of the polyester reach standards, adding the reactant into a container containing 330 parts of styrene solution, uniformly stirring, and slowly cooling to normal temperature to obtain the unsaturated polyester resin, wherein the product D is marked as the product.

Example 2:

s1, adding materials in the first step: 196 parts of neopentyl glycol, 130 parts of monoethylene glycol and 68 parts of phthalic anhydride are added into a reaction kettle, and the mixture is stirred under N₂Heating in the atmosphere, starting stirring after materials in the reaction kettle are completely melted, slowly raising the temperature to 160 ℃, then raising the temperature to 190 ℃ by a 'step gradient heating method', keeping the temperature at each step for 50min, and controlling the overall reaction time for 5h until the acid value reaches 25mgKOH/g at the end point of the polycondensation reaction.

S2, adding materials in the second step: and when the acid value of the material in the S1 reaches the standard, cooling the reaction kettle to 160 ℃, keeping the temperature for 1h, adding 26 parts of dipropylene glycol and 270 parts of maleic anhydride, continuing to heat to 200 ℃ by a 'step gradient heating method', keeping the temperature at each step for 50min, and controlling the overall reaction time to 7h until the end point of the polycondensation reaction, wherein the acid value reaches 32mgKOH/g, and the viscosity of the polyester reaches 680 mPa.s.

And S3, cooling to 160 ℃ after the acid value of the material in the S2 and the viscosity of the polyester reach standards, adding the reactant into a container containing 320 parts of styrene solution, uniformly stirring, and slowly cooling to normal temperature to obtain the unsaturated polyester resin, namely the product E.

Example 3:

s1, adding materials in the first step: 206 parts of neopentyl glycol, 144 parts of monoethylene glycol and 74 parts of phthalic anhydride are added into a reaction kettle, and the mixture is stirred under N₂Heating in the atmosphere, starting stirring after materials in the reaction kettle are completely melted, slowly raising the temperature to 170 ℃, then raising the temperature to 205 ℃ by a 'step gradient heating method', keeping the temperature at each step for 75min, and controlling the whole reaction time for 8h until the acid value reaches 20mgKOH/g at the end point of the polycondensation reaction.

S2, adding materials in the second step: and when the acid value of the material in the S1 reaches the standard, cooling the reaction kettle to 170 ℃, keeping the temperature for 1.5h, adding 28 parts of dipropylene glycol and 276 parts of maleic anhydride, continuing to heat to 215 ℃ by a step gradient heating method, keeping the temperature of each step constant for 75min, and controlling the overall reaction time for 10h until the end of the polycondensation reaction, wherein the acid value reaches 28mgKOH/g, and the viscosity of the polyester reaches 720 mPa.s.

And S3, cooling to 170 ℃ after the acid value of the material in the S2 and the viscosity of the polyester reach standards, adding the reactants into a container containing 334 parts of styrene solution, uniformly stirring, and slowly cooling to normal temperature to obtain the unsaturated polyester resin, wherein the product is marked as product F.

Uniformly mixing 100 parts of the product in the embodiment, 10 parts of low-shrinkage additive polyvinyl acetate and 0.4 part of accelerator dimethyl aminobenzene, adding 2 parts of curing agent benzoyl peroxide, uniformly stirring, curing in a mold, demolding and taking out after curing for 8 hours at 40 ℃, obtaining cured body products a, b, c, d, e and f corresponding to A, B, C, D, E, F, and testing the performance of the cured body.

The tensile strength of the cured bodies was tested according to the GB/T1040.2-2006 standard.

The cured bodies were tested for flexural strength according to the GB/T9341-2008 standard.

The impact strength of the cured bodies was tested according to the GB/T1043-93 standard.

The cured bodies were tested for Babbitt hardness according to the GB/T3854-2005 standard.

The performance parameters are shown in Table 2.

Table 2:

cured body	a	b	c	d	e	f
							Tensile strength/MPa	42	64	87	94	90	96
Flexural Strength/MPa	81	101	110	117	115	121
							Compressive strength/MPa	112	119	133	140	137	149
Impact Strength/(KJ/m)2)	6.4	7.2	9.1	9.4	9.3	9.7
							Babbitt hardness	42	48	61	67	65	68

Linear shrinkage test: cured bodies a1, b1, c1, D1, e1 and f1 prepared by the same curing process as described above were subjected to linear shrinkage tests on cured bodies a, b, c, D, e, f and a1, b1, c1, D1, e1 and f1 according to the standard test of ASTM D2566-1986 without adding polyvinyl acetate as a low shrinkage additive to product A, B, C, D, E, F, and the results are shown in table 3.

Table 3:

and (3) testing water resistance: and completely soaking the solidified body sample in tap water of the same water source, keeping the temperature of the solidified body sample constant at 50 ℃, taking out the solidified body sample after 30 days, airing, marking the corresponding solidified body samples as a2, b2, c2, d2, e2 and f2, and testing the mechanical properties of the solidified body sample according to the standards, wherein the results are shown in table 4.

Table 4:

cured body	a2	b2	c2	d2	e2	f2
							Tensile strength/MPa	27	61	41	92	89	94
Flexural Strength/MPa	42	100	61	114	112	117
							Compressive strength/MPa	65	115	98	138	136	145
Impact Strength/(KJ/m)2)	2.9	6.9	4.1	9.2	9.0	9.6
							Babbitt hardness	27	41	42	64	62	65

And (3) corrosion resistance test: the solidified body sample was placed in a 20% hydrochloric acid solution and a 20% sodium hydroxide solution, and the degree of corrosion of the surface of the solidified body sample was observed at 80 ℃ for various periods of time, and the results are shown in table 5.

Table 5:

as can be seen from Table 2, the relevant mechanical properties of d, e and f are effectively improved compared with those of a, b and c, the neopentyl glycol can optimize the structure of the unsaturated polyester resin, so that the mechanical properties are improved, the mechanical properties of the cured unsaturated polyester resin can be greatly improved by using a small amount of high-performance dipropylene glycol, and the comprehensive mechanical properties of the cured unsaturated polyester resin can be further improved by compounding the neopentyl glycol with the high-performance dipropylene glycol.

As can be seen from table 3, the linear shrinkage of the cured product of the C, D, E, F product is greatly reduced after the low shrinkage additive polyvinyl acetate is added compared with that of the A, B product, which indicates that the compatibility of dipropylene glycol and the low shrinkage additive is better, and the linear shrinkage of the cured product can be greatly reduced by matching the low shrinkage additive, so that the C, D, E, F product is suitable for manufacturing general molding compound products and automobile accessories such as bumpers, fairings and the like.

It is known from the comparison between tables 4 and 3 that neopentyl glycol can greatly improve the water resistance of unsaturated polyester resin, and after the cured product of neopentyl glycol is subjected to 30 water resistance test, the comprehensive mechanical properties of b2, d2, e2 and f2 are only reduced to a small extent, while the comprehensive mechanical properties of the cured products a2 and c2 which do not adopt neopentyl glycol are greatly reduced.

As can be seen from Table 5, b, d, e and f have better corrosion resistance than a and c, and the corrosion resistance of the cured product of the unsaturated polyester resin can be obviously improved by adopting neopentyl glycol under the conditions of the formula ratio and parameters of the invention.