Heat-resistant agent for transparent material and preparation method of heat-resistant agent

Abstract

The invention relates to a heat-resistant agent for a transparent material and a preparation method of the heat-resistant agent, the heat-resistant agent is prepared from the following raw materials in parts by weight: 30-75 parts of an acrylate monomer, 10-30 parts of an aromatic vinyl monomer, 5-40 parts of a maleimide substance and 0.3-0.5 part of an initiator, and the heat-resistant agent is prepared by a suspension polymerization method. The heat-resistant agent prepared by the invention has excellent heat stability and glass transition temperature, the transparency of the transparent plastic is not influenced after the transparent plastic is added, the preparation process is simple, environment-friendly and low in cost, and the heat-resistant agent can be applied to engineering plastics with requirements on transparency and heat resistance.

Description

Technical Field

[0001] The invention belongs to the field of polymer material modification and relates to a heat-resistant agent for transparent materials and a preparation method thereof. Background Art

[0002] Transparent plastics include PMMA, PS, PC, transparent ABS, etc., which are generally used in the fields of insulating parts, decorations and optical instruments, and have excellent transparent appearance and good mechanical properties. In industry, PMMA is a commonly used transparent material, which has excellent optical properties, mechanical properties, low cost and weather resistance, but its poor heat resistance limits its application in the fields of automobiles, medical equipment and electronic appliances. Therefore, under the premise of ensuring the transparency of PMMA, improving the heat resistance of PMMA and broadening its application areas are topics that researchers have been exploring.

[0003] At present, due to the good heat resistance of the five-membered ring in the imide structure, the common heat-resistant agents on the market are mainly maleimide copolymers, but most maleimide copolymer heat-resistant agents will reduce their transparency after being added to transparent plastics, such as PMMA, for extrusion granulation, and cannot meet the requirements of both heat resistance and transparency. Conventionally, the commonly used transparent materials in industry require a transmittance of more than 90% to be better used.

[0004] Moreover, the existing maleimide copolymer heat-resistant agent adopts a solution polymerization method, the production process is not environmentally friendly, the process is relatively complicated, and it is not conducive to large-scale batch production. Summary of the invention

[0005] The purpose of the present invention is to provide a heat-resistant agent for transparent materials and a preparation method thereof in view of the shortcomings of the prior art. The heat-resistant agent produced by the present invention not only has excellent heat-resistant effect, but also can produce transparent bead particles, which is suitable for modified transparent materials that require both high heat resistance and transparency.

[0006] The purpose of the present invention is achieved through the following technologies: A heat-resistant agent for transparent materials. The raw materials for preparing the heat-resistant agent for transparent materials include acrylic ester monomers, styrene substances and maleimide substances.

[0007] In the present invention, the acrylic acid ester monomer includes one or more of methyl methacrylate, ethyl methacrylate, butyl methacrylate, methyl acrylate or butyl acrylate; the styrene-based substance includes an aromatic vinyl monomer, specifically, the aromatic vinyl monomer includes one or more of styrene, methyl styrene, and ethyl styrene; the maleimide-based substance includes one or more of N-phenylmaleimide, N-cyclohexylmaleimide, and bismaleimide-based monomers.

[0008] The present invention discloses a method for preparing the heat-resistant agent for transparent materials, comprising the following steps: the raw materials for preparing the heat-resistant agent for transparent materials are polymerized to obtain the heat-resistant agent for transparent materials. Furthermore, acrylate monomers, styrene substances and maleimide substances are mixed and polymerized to obtain the heat-resistant agent for transparent materials.

[0009] In the present invention, the weight ratio of acrylate monomers, styrene substances and maleimide substances is (30-75): (10-30): (5-40). Preferably, the weight ratio of acrylate monomers, styrene substances and maleimide substances is (40-65): (10-20): (20-40). More preferably, the weight ratio of acrylate monomers, styrene substances and maleimide substances is (50-65): (10-20): (20-35), and more preferably, the weight ratio of acrylate monomers, styrene substances and maleimide substances is (55-65): (12-18): (20-30), such as 55:15:30, 65:15:20, or other ratios within this range.

[0010] In the present invention, the polymerization reaction is an initiated polymerization reaction, and the initiator used includes one or more of an azo initiator and a peroxide initiator; the polymerization reaction temperature is 50-100°C, and the time is 1-10 hours. Preferably, the polymerization reaction temperature is 55-90°C, and the time is 2-8 hours. More preferably, the polymerization reaction temperature is 60-80°C, and the time is 3-6 hours. Further, the polymerization reaction is followed by aging to obtain a heat-resistant agent for transparent materials. The aging is 80-105°C for 0.5-5 hours, and preferably, the aging is 90-95°C for 1-2 hours.

[0011] In the present invention, the polymerization reaction is carried out in the presence of a molecular weight regulator; the molecular weight regulator is selected from one of 2,4-diphenyl-4-methyl-1-pentene, tert-dodecyl mercaptan, and 3-mercaptoacrylate isooctyl ester. The amount of the molecular weight regulator used is 0.05-0.5% of the total weight of the acrylate monomer, the styrene substance, and the maleimide substance, preferably 0.05-0.2%, and more preferably 0.08-0.12%, such as 0.08%, 0.09%, 0.1%, 0.11%, 0.12%, or any value within the range.

[0012] In the present invention, water is used as a solvent for the polymerization reaction. The present invention adopts suspension polymerization, which solves the problem that the production process of solution polymerization in the prior art is not environmentally friendly, the process is relatively complicated, and it is not conducive to large-scale batch production. In addition, the polymerization of the present invention can produce transparent bead particles, which are suitable for modified transparent materials that require both high heat resistance and transparency.

[0013] As an example, acrylate monomers, styrene substances, maleimide substances and water are mixed, and then an initiator and a molecular weight regulator are added to undergo a polymerization reaction, followed by aging to obtain a heat-resistant agent for transparent materials in the form of transparent particles.

[0014] The invention discloses the application of the heat-resistant agent for transparent materials in preparation or as a plastic modifier.

[0015] The present invention discloses the use of the heat-resistant agent for transparent materials in the preparation of plastics. Preferably, the plastics include transparent plastics, including PMMA, PC, transparent ABS, transparent PS, etc.; for example, the heat-resistant agent is applied to transparent materials PMMA, PC, transparent ABS, PS, etc.

[0016] The invention discloses a plastic, the raw materials for preparing the plastic include the heat-resistant agent for transparent materials. Specifically, the heat-resistant agent for transparent materials is added as a modifier to the raw materials for preparing the plastic to obtain a plastic product.

[0017] Compared with the prior art, the present invention has the following effects: 1. The system uses suspension polymerization to prepare heat-resistant agent. This heat-resistant agent has excellent heat resistance and good transparency, which meets the market requirements for transparent heat-resistant agent. 2. The system has a simple preparation process, is environmentally friendly, and can be mass-produced; 3. This process can control the molecular weight and distribution of the polymer to obtain a polymer with a narrow molecular weight distribution; 4. This heat-resistant agent can be directly applied to the heat-resistant modification of PMMA. It has good compatibility and heat resistance, which can expand the application field of PMMA. It can also be used in the heat-resistant modification process of other transparent materials to improve the application performance of materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Other features, objects and advantages of the present invention will become more apparent from the detailed description of non-limiting embodiments made with reference to the following accompanying drawings.

[0019] Figure 1 Heat resistant polymer A 2 The glass transition temperature.

[0020] Figure 2 Heat resistant polymer B 1 The glass transition temperature.

[0021] Figure 3 Heat resistant polymer B 2 The glass transition temperature.

[0022] Figure 4Heat resistant polymer A 2 Infrared spectrum of .

[0023] Figure 5 This is the appearance of different heat-resistant agents after tableting.

[0024] Figure 6 This is the appearance of acrylic modified with different heat-resistant agents. DETAILED DESCRIPTION

[0025] The heat-resistant agent of the present invention is a copolymer obtained by polymerization reaction of acrylic ester monomers, styrene substances and maleimide substances in the presence of conventional auxiliary agents (such as initiators and molecular weight regulators). Specifically, the present invention discloses a method for preparing the heat-resistant agent for transparent materials, comprising the following steps: (1) Mix acrylate monomers, aromatic vinyl monomers and maleimide substances in a certain proportion, add water, stir evenly, add initiator and molecular weight regulator, the polymerization temperature is 60-80°C, and the constant temperature reaction time is 3-6 hours; (2) After the constant temperature reaction is completed, the mixture is aged at 90-95°C for 1-2 hours, filtered and dried to obtain a heat-resistant agent for transparent materials, which is a random copolymer with an imine structure. The product is transparent colorless / light yellow bead-like particles, and the glass transition temperature of the heat-resistant agent is between 150 and 200°C.

[0026] In the present invention, the weight ratio of the sum of the weight of acrylate monomers, styrene substances and maleimide substances and water is 1: (0.5-5), preferably, the weight ratio of the sum of the weight of acrylate monomers, styrene substances and maleimide substances and water is 1: (1-3), and further preferably, the weight ratio of the sum of the weight of acrylate monomers, styrene substances and maleimide substances and water is 1: (1.5-2.5).

[0027] In the present invention, the initiator includes one of an azo initiator and a peroxide initiator; the amount of the initiator used is 0.1 to 1% of the total weight of the acrylate monomer, the styrene substance and the maleimide substance, preferably 0.2 to 0.6%, and further preferably 0.2 to 0.5%, such as 0.2%, 0.3%, 0.4%, 0.5% or any value within the range.

[0028] The heat-resistant agent of the present invention is applied to transparent materials, such as PMMA, PC, transparent ABS, PS, etc. As an application example, the transparent material, the antioxidant, and the heat-resistant agent are uniformly mixed to obtain a premix, and the premix is ​​placed in a screw extruder for extrusion and granulation. The transparency of the modified heat-resistant transparent material is almost equivalent to that of pure plastic.

[0029] The present invention is described in detail below in conjunction with specific embodiments. The following examples will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those of ordinary skill in the art, without departing from the inventive concept, several variations and improvements can also be made. These all belong to the protection scope of the present invention. The raw materials used in the present invention are conventional products in the art, and specific preparation operations and performance tests are all conventional techniques. Unless otherwise specified, parts hereinbelow refer to parts by weight, and each part is 1 kilogram.

[0030] The preparation method of the transparent heat-resistant agent of the present invention is as follows: acrylic acid ester monomer, styrene substance and maleimide substance are mixed according to certain weight parts and added into a polymerization reaction kettle, water is added, stirred evenly, initiator and molecular weight regulator are added, the polymerization temperature is 60-80°C, and the constant temperature reaction time is 3-6h; after the constant temperature reaction is completed, the temperature is continued to rise to 90-95°C, matured for 1-2h, filtered and dried to obtain transparent light yellow bead particles; the polymer is a random copolymer with excellent heat resistance. Adding transparent plastic for granulation modification can obtain transparent heat-resistant modified plastic. Example 1

[0031] Weigh 65 parts by weight of methyl methacrylate MMA, 15 parts of styrene ST, and 20 parts of N-phenylmaleimide NPMI, mix them evenly, add 200 parts of water, stir for 30 minutes, then add 0.3 parts of AIBN and 0.1 parts of tert-dodecyl mercaptan, react at 65°C for 5 hours, react at 95°C for 1.5 hours after the reaction is completed, then cool naturally to room temperature, collect the reactants, filter and dry to obtain transparent light yellow bead particles A 1 . Example 2

[0032] Weigh 55 parts of MMA, 15 parts of ST, and 30 parts of NPMI by weight, mix them evenly, add 200 parts of water, stir for 30 minutes, then add 0.3 parts of AIBN and 0.1 parts of tert-dodecyl mercaptan, react at 65°C for 5 hours, react at 95°C for 1.5 hours after the reaction is completed, then cool naturally to room temperature, collect the reactants, and then filter and dry to obtain transparent light yellow bead particles A 2 . Example 3

[0033] Weigh 45 parts of MMA, 15 parts of ST, and 40 parts of NPMI by weight, mix them evenly, add 200 parts of water, stir for 30 minutes, then add 0.3 parts of AIBN and 0.1 parts of tert-dodecyl mercaptan, react at 65°C for 5 hours, react at 95°C for 1.5 hours after the reaction is completed, then cool naturally to room temperature, collect the reactants, and then filter and dry to obtain transparent light yellow bead particles A3 . Comparative Example 1

[0034] Weigh 10 parts of MMA, 60 parts of ST, and 30 parts of NPMI by weight, mix them evenly, add 200 parts of water, stir for 30 minutes, then add 0.3 parts of AIBN and 0.1 parts of tert-dodecyl mercaptan, react at 65°C for 5 hours, react at 95°C for 1.5 hours after the reaction is completed, then cool naturally to room temperature, collect the reactants, and then filter and dry to obtain transparent light yellow bead particles B 1 . Comparative Example 2

[0035] Weigh 10 parts of MMA, 50 parts of ST, and 40 parts of NPMI by weight, mix them evenly, add 200 parts of water, stir for 30 minutes, then add 0.3 parts of AIBN and 0.1 parts of tert-dodecyl mercaptan, react at 65°C for 5 hours, react at 95°C for 1.5 hours after the reaction is completed, then cool naturally to room temperature, collect the reactants, and then filter and dry to obtain transparent light yellow bead particles B 2 . Comparative Example 3

[0036] The commercially available competitor SMA resin is a styrene-maleic anhydride copolymer, with slightly yellow transparent particles, denoted as B 3 . Comparative Example 4

[0037] The commercial competitor SMI resin is a styrene-N-phenylmaleimide binary copolymer, light yellow powder particles, denoted as B 4 . Comparative Example 5

[0038] The commercial competitor BP-356M resin is a terpolymer of styrene-methyl methacrylate-maleic anhydride, with natural color and high transparency particles, denoted as B 5 . Performance Testing

[0039] Infrared test: Tested using Fourier transform infrared spectrometer; Thermal gravimetric test: Tested according to ASTM D6370-99 standard, using TGA, heating rate 20℃ / min, N 2 atmosphere, taking 5% weight loss as the initial thermal decomposition temperature; DSC test: Tested according to ASTM E1356 standard, heating rate 10℃ / min, N 2 atmosphere; Vicat softening point: The test is carried out in accordance with ISO 306 standard; Color haze meter: tested according to ASTM D1003 standard; The polymers prepared in the examples and comparative examples were subjected to performance tests, and various indicators and results are shown in Table 1.

[0040] Table 1 Test results of polymer properties prepared in Examples 1 to 3 and Comparative Examples 1 to 3

[0041] Examples 1 to 3 are heat-resistant copolymers with different NPMI contents. As shown in Table 1, as the NPMI content increases, the glass transition temperature Tg gradually increases, and there is only one Tg value, such as Figure 1 As shown, it is the heat-resistant polymer A of the present invention 2 DSC curve; while the raw materials of Comparative Example 1 and Comparative Example 2 are the same as those of Example 1, and are heat-resistant copolymers with different NPMI contents, the difference in the ratio leads to the appearance of two Tg peaks, and the composition of the polymer is not uniform, and it is a substandard product, see Figure 2 as well as Figure 3 , respectively polymer B 1 , B 2 DSC curve of .

[0042] Depend on Figure 4 Heat Resistant Polymer A 2 The infrared image shows that the MMA-ST-NPMI ternary random copolymer has been successfully synthesized, with 1777 and 1705 cm -1 V C=O and 1180cm -1 V C-N It is the characteristic absorption peak of NPMI.

[0043] Comparative Example 3 is a commercially available heat-resistant agent with good production application. According to the Tg value, Example 2 can meet the market application demand for heat-resistant agents, and the thermal decomposition temperature of the polymer is above 300°C, which can meet the granulation processing technology of transparent plastics.

[0044] Application Examples The composition and proportion of the polymer of this embodiment are shown in Table 2. The preparation method is as follows: the above-mentioned heat-resistant agent is mixed with PMMA and antioxidant (1010, 168, equal proportion) in a high-speed mixer to obtain a premix; the premix is ​​placed in a twin-screw extruder and extruded into granules, which is specifically a conventional method.

[0045] Table 2 PMMA application evaluation comparative examples and example formulation ratios (by weight)

[0046] like Figure 5As shown in Table 2, the particles of Example 2 and Comparative Examples 3 to 5 are pressed into sheets. From the appearance, except for Comparative Example 4, which has the worst transparency, the transparency of the other pressed sheets is equivalent. However, when the comparative examples are used in PMMA or other substrates, the light transmittance of the modified materials decreases to less than 90%, as shown in Table 2. From the appearance, the PMMA modified in Example 2 of the present invention has the best light transmittance, as shown in Table 2. Figure 6 As shown, the haze is also small, at 7.5%; at the same time, the improvement in thermal performance is small. This shows that adding a heat-resistant agent with MMA to the copolymer does not necessarily achieve the effect of improving heat resistance and maintaining light transmittance.

[0047] The application evaluation results are shown in Table 2. The results show that: Examples 4 to 6, add 10 parts of A 1 , A 2 or A 3 The transmittance of subsequent samples was above 90%, so the addition of this heat-resistant polymer had almost no effect on the transparency of PMMA.

[0048] Comparative Examples 6 to 10, add the same amount of B 1 , B 2 , B 3 , B 4 and B 5 , the light transmittance is lower than that of the embodiment. Under the condition of the same content of NPMI, the haze of the comparative example is higher than that of the embodiment. Therefore, the polymerization ratio of MMA to ST has a certain influence on the transparency of the heat-resistant modified PMMA. The light transmittance of comparative examples 8 to 10 is lower than that of embodiments 4 to 6, and the haze is higher than that of the embodiment. Therefore, the heat-resistant agent of the present invention has an advantage over the heat-resistant agent on the market, which can improve the heat resistance of PMMA and does not affect the transparency of PMMA.

[0049] Expand your application The obtained heat-resistant agent A 2 The premix is ​​prepared by mixing the premix with PC, transparent ABS and transparent PS (adding amount 10wt%) in a high-speed mixer (adding conventional antioxidants, 0.3%-0.4%, 1010, 168, equal proportions) to obtain a premix; the premix is ​​put into a twin-screw extruder, extruded into granules, and then conventionally tableted, specifically by a conventional method. The heat-resistant modified plastic obtained also has good light transmittance and can replace pure plastics for industrial applications.

[0050] The above describes the specific embodiments of the present invention. It should be understood that the present invention is not limited to the above specific embodiments, and those skilled in the art can make various modifications or variations within the scope of the claims, which does not affect the essence of the present invention.

Claims

1. A heat-resistant agent for transparent materials, characterized in that: The raw materials for preparing the heat-resistant agent for transparent materials include acrylic ester monomers, styrene substances and maleimide substances.

2. The heat-resistant agent for transparent materials according to claim 1, characterized in that: The acrylic acid ester monomers include one or more of methyl methacrylate, ethyl methacrylate, butyl methacrylate, methyl acrylate or butyl acrylate; the styrene substances include one or more of aromatic vinyl monomers; the maleimide substances include one or more of N-phenylmaleimide, N-cyclohexylmaleimide and bismaleimide monomers.

3. The heat-resistant agent for transparent materials according to claim 1, characterized in that: The weight ratio of the acrylic acid ester monomer, the styrene substance and the maleimide substance is (30-75): (10-30): (5-40).

4. The method for preparing the heat-resistant agent for transparent materials according to claim 1, characterized in that: Preparation of heat-resistant agent for transparent material The heat-resistant agent for transparent material is obtained by polymerization reaction of raw materials.

5. The method for preparing a heat-resistant agent for transparent materials according to claim 4, characterized in that: The polymerization reaction is an initiated polymerization reaction, and the initiator includes one or more of an azo initiator and a peroxide initiator; the polymerization reaction temperature is 60 to 80° C., and the time is 3 to 6 hours.

6. The method for preparing a heat-resistant agent for transparent materials according to claim 4, characterized in that: After the polymerization reaction, the product is aged to obtain a heat-resistant agent for transparent materials.

7. The method for preparing a heat-resistant agent for transparent materials according to claim 4, characterized in that: The polymerization reaction is carried out in the presence of a molecular weight regulator; the polymerization reaction uses water as solvent.

8. Use of the heat-resistant agent for transparent materials according to claim 1 as or in the preparation of a plastic modifier.

9. A plastic, characterized in that: The raw materials for preparing the plastic include the heat-resistant agent for transparent materials as claimed in claim 1.

10. Use of the heat-resistant agent for transparent materials according to claim 1 in the preparation of plastics.

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