A transparent copolymer resin, a method for preparing the same, and a resin composition comprising the same

Abstract

The present invention provides a method for preparing a styrene-acrylonitrile-acrylate terpolymer transparent resin and a resin composition comprising the same. The transparent resin has lower odor, lower processing temperature, and good color phase, high transparency due to good flowability; and the temperature dependence of the refractive index of the transparent resin is low, thereby reducing the defect of the optical performance of the transparent ABS resin deteriorating with temperature change.

Description

Technical Field

[0001] This invention relates to a transparent copolymer resin, its preparation method, and a resin composition comprising the transparent copolymer resin, belonging to the field of polymer materials. Background Technology

[0002] Styrene-acrylonitrile-acrylate terpolymer is a transparent resin that can be used alone as a plastic, but it is mainly mixed with acrylonitrile-butadiene-styrene (ABS) grafted rubber to prepare transparent ABS.

[0003] Transparent ABS resin is often used in washing machine lids, windows and other parts. It can be prepared by co-extrusion of grafted rubber (powder phase) and matrix resin (resin phase). Whether the refractive index of the two phases is consistent determines whether transparent ABS has good optical properties.

[0004] Chinese patent CN1372579A discloses a styrene-acrylonitrile-methyl methacrylate terpolymer prepared by bulk polymerization. By controlling the ratio of monomers, the refractive index of the resin is adjusted to be in the range of 1.513-1.521, thus obtaining a transparent ABS resin composition.

[0005] Chinese patent CN101072803A discloses a resin composition with good transparency, drug resistance and fading resistance prepared by bulk polymerization of styrene monomer, methyl methacrylate monomer and acrylonitrile monomer and antioxidant.

[0006] The copolymers of styrene monomer, methyl methacrylate monomer and acrylonitrile monomer disclosed in the above patent documents, as well as the transparent ABS resin prepared by blending with acrylonitrile-butadiene-styrene (ABS) grafted rubber, are mainly used to improve transparency and introduce antioxidants to alleviate the presence of acrylonitrile and styrene with poor heat resistance, thereby optimizing the resin color. However, the introduction of antioxidants causes a certain degree of loss in the transparency of the resin.

[0007] It is known that most commercially available transparent ABS resins are prepared by blending the adhesive powder phase and the resin phase. The key technology is to control the refractive index of the two phases to be consistent, thereby enabling the ABS resin to achieve transparency at a certain temperature. As is well known, the refractive index of a polymer has a certain temperature dependence, decreasing as the temperature increases. Because the refractive indices of the two phases have different corresponding relationships within a certain temperature range, the optical performance of transparent ABS will decrease under different temperature conditions, leading to fogging of the product. For example, the water heating function of a washing machine may affect the viewing effect through the window.

[0008] The temperature dependence of refractive index is essentially related to the mobility of polymer molecular chains. The more flexible the molecular chains, i.e., the lower the glass transition temperature, the less temperature affects the refractive index, and vice versa. In other words, for transparent ABS prepared by blending, because the molecular chains of the powder phase are more flexible and the molecular chains of the resin phase are more rigid, the trend of their refractive index changes is inconsistent with temperature changes. This will cause transparent ABS to gradually become hazy with temperature changes, resulting in a deterioration in optical performance.

[0009] Therefore, it is essential to develop a styrene-acrylonitrile-acrylate resin with high transparency, good flowability, and low temperature dependence of refractive index. Summary of the Invention

[0010] To address the above technical problems, this invention provides a method for preparing a transparent copolymer resin. More specifically, this invention relates to a method for preparing a styrene-acrylonitrile-acrylate terpolymer transparent resin and a resin composition comprising the styrene-acrylonitrile-acrylate terpolymer transparent resin. This transparent resin exhibits low odor, low processing temperature, and good hue due to its good flowability, resulting in high transparency. Furthermore, the transparent resin phase has a low temperature dependence of refractive index, thereby reducing the defect of deteriorating optical properties of transparent ABS resin with temperature changes.

[0011] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0012] A styrene-acrylonitrile-acrylate terpolymer transparent resin, wherein the terpolymer transparent resin exhibits low temperature dependence of refractive index within a temperature range of 10 to 60°C, and the relationship between its refractive index y and temperature x (°C) satisfies the linear relationship: y = a1x + b1, where a1 is in the range of -0.03% to -0.01%, b1 is in the range of 1.5 to 1.6, and it has a refractive index of 1.520-1.510.

[0013] The present invention also provides a method for preparing the above-mentioned styrene-acrylonitrile-acrylate terpolymer transparent resin.

[0014] A method for preparing a transparent copolymer resin, the method comprising the following steps:

[0015] a) Mix aromatic vinyl monomers, (meth)acrylate alkyl ester monomers, unsaturated nitrile monomers, organic peroxide initiator A, chain transfer agent and reaction medium to obtain a reaction mixture;

[0016] b) Add the reaction mixture described in a) to reactor 1) to carry out a bulk polymerization reaction at a reaction temperature of 130-145°C. The reaction temperature of reactor 1) is controlled by a gas-phase circulating liquid, wherein the temperature of the gas-phase circulating liquid is 30-40°C and the proportion of reaction medium in the circulating liquid is 15-25%. Control the bulk polymerization conversion rate to 50-55% to obtain a polymerized mixture.

[0017] c) Add the polymerization mixture described in b) and organic peroxide initiator B to reactor 2) to carry out bulk polymerization. The reaction temperature is 145-155℃, the temperature of the gas phase circulating liquid in reactor 2) is 20-30℃, and the proportion of reaction medium in the circulating liquid is 35-45%. Control the bulk polymerization conversion rate to 75-80% to obtain the polymerization mixture.

[0018] d) After step c) is completed, the polymer mixture is transferred to a devolatilization tank to remove the light components, yielding a transparent copolymer resin.

[0019] In the preparation method of the present invention, preferably, the amount of each component in step a) is: 50-70 parts by weight of alkyl methacrylate monomer, 10-30 parts by weight of aromatic vinyl monomer, 5-20 parts by weight of unsaturated nitrile monomer and 10-20 parts by weight of reaction medium.

[0020] Preferably, in step a), based on 100 parts by weight of the aromatic vinyl monomer, (meth)acrylate alkyl ester monomer, unsaturated nitrile monomer and reaction medium mixture described in a), the amount of organic peroxide initiator A added is 0.01 to 0.03 parts by weight, and the amount of chain transfer agent added is 0.05 to 0.2 parts by weight.

[0021] In the preparation method of the present invention, preferably in step c), the amount of organic peroxide initiator B added is 0.002 to 0.005 parts by weight based on 100 parts by weight of the mixture of initial raw materials and reaction medium.

[0022] In the preparation method of the present invention, preferably, in step d), the devolatilization temperature is 210-240°C, the absolute pressure is 3-10 kPa, and the devolatilization time is 10-15 min.

[0023] Preferably, the alkyl methacrylate monomer used to prepare the transparent copolymer resin of the present invention includes one or more of methyl methacrylate, ethyl methacrylate, methyl acrylate, ethyl acrylate, and butyl acrylate; more preferably, the alkyl methacrylate is methyl methacrylate.

[0024] Preferably, the aromatic vinyl monomer used to prepare the transparent copolymer resin of the present invention includes at least one of styrene and α-methylstyrene; more preferably, the aromatic vinyl monomer is styrene.

[0025] Preferably, the unsaturated nitrile monomer used to prepare the transparent copolymer resin of the present invention includes at least one of acrylonitrile and methacrylonitrile; more preferably, the unsaturated nitrile monomer is acrylonitrile.

[0026] Preferably, the reaction medium used in this invention is one or more of cyclohexane, toluene, xylene, and ethylbenzene, with toluene being the most preferred.

[0027] Preferably, the organic peroxide initiator A used in this invention is at least one of 1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane and 1,1-bis(tert-butylperoxy)cyclohexane; and the organic peroxide initiator B is one or more of cumene peroxide and dicumene peroxide, more preferably dicumene peroxide.

[0028] Preferably, the chain transfer agent used in this invention is a thiol-based compound, including at least one of tert-dodecyl thiol and n-octyl thiol; more preferably, the chain transfer agent is n-octyl thiol.

[0029] The transparent copolymer resin prepared by the method of the present invention has a glass transition temperature of 80-95°C, a molecular weight distribution of 2.0-2.3, a monomer residue of 1000 ppm or less, a melt index of 30 or higher, a b color value of 1 or lower, and a refractive index of 1.520-1.510 within a temperature range of 10-60°C with low temperature dependence.

[0030] This invention also relates to the application of the styrene-acrylonitrile-acrylate terpolymer transparent resin in the preparation of transparent ABS resin.

[0031] The transparent copolymer resin can be blended with acrylonitrile-butadiene-styrene resin to prepare transparent ABS resin. This transparent ABS resin composition contains 50-85% of the aforementioned transparent copolymer resin and 15-50% of ABS resin, and may also include other conventional additives. In addition to the aforementioned excellent physical properties, this transparent ABS exhibits a low temperature dependence on its refractive index.

[0032] The beneficial effects of this invention are as follows:

[0033] The transparent resin prepared by this invention has a low temperature dependence of phase refractive index, thereby reducing the defect of the optical performance of transparent ABS resin deteriorating with temperature changes. Attached Figure Description

[0034] Figure 1This is a schematic diagram of one reaction method of the present invention. Detailed Implementation

[0035] The present invention will be further illustrated below with specific embodiments. These embodiments are merely illustrative and do not limit the scope of the invention.

[0036] The test methods for copolymer-related structures and properties are as follows:

[0037] Glass transition temperature (Tg): Measured using a Swiss METTLER instrument, unit: °C;

[0038] Relative molecular mass (Mw) and molecular weight distribution (PDI): measured using a Shimadzu 20AD instrument, Japan. The unit for relative molecular mass is g / mol.

[0039] Monomer residue (GC): Tested using an Agilent 7890B instrument, unit: ppm;

[0040] Color (b value): The yellowness index of the sample was measured using a Hunter Lab colorimeter;

[0041] Melt flow index (MFR): Tested using a CEAST MF30 melt flow indexer, unit: g / 10min;

[0042] Refractive index (RI): Measured for 2mm injection molded sheet according to ASTM standard D 542.

[0043] Haze value (H): The haze value of a 2mm injection molded sheet is measured according to ASTM D1003.

[0044] The linear relationship y=a1x+b1: The refractive index of a 2mm injection molded sheet sample at 10℃ / 20℃ / 30℃ / 40℃ / 50℃ / 60℃ is measured. Plotting the temperature on the x-axis, a1 and b1 are obtained by linear fitting.

[0045] The main raw material information is shown in Table 1:

[0046] Table 1. Information on Main Raw Materials

[0047] Preparation of transparent ABS:

[0048] 0.2 parts by weight of EBS, 0.1 parts by weight of 1076, 0.2 parts by weight of 618, and 0.2 parts by weight of magnesium stearate were added to a mixture consisting of 15 parts by weight of HR181 and 85 parts by weight of the transparent copolymer resin of the example / comparative example and blended. Particle resin was prepared by twin-screw extruder at 220°C, and optical sheets were injection molded at 220°C. The physical properties of transparent ABS were then tested.

[0049]

Example 1

[0050] The transparent copolymer resin was prepared according to the following method:

[0051] Using a free-basic polymerization method, 1000g of toluene, 3500g of methyl methacrylate, 1000g of styrene, 500g of acrylonitrile, 4.8g of n-octyl mercaptan, and 1.2g of 1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane were mixed in reactor 1) with a gas-phase circulating liquid. The reactor was heated to 140℃ for reaction. When the proportion of toluene in the gas-phase circulating liquid was 15-20wt% and the temperature was 30-40℃, the polymerization mixture was transferred to reactor 2), and 0.24g of dicumyl peroxide was added. The reaction continued at 150℃. When the proportion of toluene in the gas-phase circulating liquid was 35-45wt% and the temperature was 20-30℃, the polymerization mixture was transferred to a devolatilization tank. The devolatilization tank was heated to 220℃ and gradually evacuated to a vacuum degree of -0.1MPa, maintained for 15min, and after removing unpolymerized monomers, a transparent copolymer resin was obtained. The product analysis and copolymer performance test results, as well as the properties of the prepared transparent ABS, are shown in Table 1.

[0052] Examples 2-6

[0053] The transparent copolymer resin was prepared using a process that was essentially the same as in Example 1. The changes in the process, product analysis, copolymer performance test results, and the properties of the prepared transparent ABS are shown in Table 1.

[0054] Comparative Example 1

[0055] The transparent copolymer resin was prepared using a process essentially the same as in Example 1, employing a free-base polymerization method. In reactor 1) with a gas-phase circulating liquid, 1000g of toluene, 3500g of methyl methacrylate, 1000g of styrene, 500g of acrylonitrile, 4.8g of n-octyl mercaptan, and 1.2g of 1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane were mixed. The reactor was heated to 140°C for reaction. When the toluene content in the gas-phase circulating liquid reached 15-20 wt% and the temperature was 30-40°C, the polymerization mixture was transferred to reactor 2), and 0.24g of [unspecified ingredient] was added. 1,1-Bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane was reacted at 150℃. When the toluene content in the gas-phase circulating liquid was 35-45 wt% and the temperature was 20-30℃, the polymerization mixture was transferred to a devolatilization tank. The devolatilization tank was heated to 220℃ and gradually evacuated to a vacuum of -0.1 MPa, held for 15 min, and after removing unpolymerized monomers, a transparent copolymer resin was obtained. The product analysis, copolymer performance test results, and the properties of the prepared transparent ABS are shown in Table 1.

[0056] Comparative Example 2

[0057] The transparent copolymer resin was prepared using a process essentially the same as in Example 1. A free monomer polymerization method was employed. In reactor 1) with a gas-phase circulating liquid, 1000g toluene, 3500g methyl methacrylate, 1000g styrene, 500g acrylonitrile, 4.8g n-octyl mercaptan, and 1.2g dicumyl peroxide were mixed. The reactor was heated to 140°C for reaction. When the toluene content in the gas-phase circulating liquid was 15-20 wt% and the temperature was 30-40°C, the polymerization mixture was transferred to reactor 2), and 0.24g dicumyl peroxide was added. The reaction continued at 150°C. When the toluene content in the gas-phase circulating liquid was 35-45 wt% and the temperature was 20-30°C, the polymerization mixture was transferred to a devolatilization tank. The devolatilization tank was heated to 220°C and gradually evacuated to a vacuum of -0.1 MPa, held for 15 minutes, and unpolymerized monomers were removed to obtain the transparent copolymer resin. The product analysis and copolymer performance test results, as well as the properties of the prepared transparent ABS, are shown in Table 1.

[0058] Comparative Example 3

[0059] A transparent copolymer resin was prepared using a process essentially the same as in Example 1, employing a free-base polymerization method. In reactor 1) with a gas-phase circulating liquid, 1000g toluene, 3500g methyl methacrylate, 1000g styrene, 500g acrylonitrile, 4.8g n-octyl mercaptan, and 1.2g... 1,1-Bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane was used. The reactor was heated to 140°C for reaction. When the toluene content in the gas-phase circulating liquid was 15-20 wt% and the temperature was 30-40°C, the polymerization mixture was transferred to reactor 2), and 0.24 g of dicumyl peroxide was added. The reaction continued at 140°C. When the toluene content in the gas-phase circulating liquid was 35-45 wt% and the temperature was 20-30°C, the polymerization mixture was transferred to a devolatilization tank. The devolatilization tank was heated to 220°C and gradually evacuated to a vacuum of -0.1 MPa, maintained for 15 min, and after removing unpolymerized monomers, a transparent copolymer resin was obtained. The product analysis, copolymer performance test results, and the properties of the prepared transparent ABS are shown in Table 1.

[0060] According to the test results in Table 1, the transparent copolymer resins prepared in Examples 1-6 of the present invention have high fluidity, low monomer residue and whiter color; at the same time, the temperature dependence of the refractive index is lower in the range of 10-60℃.

[0061] Table 1. Reaction conditions and product test results of Examples 1-6 and Comparative Examples 1-3

[0062]

[0063] Table 1 (continued)

[0064]

[0065]

Claims

1. A styrene-acrylonitrile-acrylate terpolymer transparent resin, wherein the terpolymer transparent resin has a refractive index y that satisfies the linear relationship with temperature x℃ within a temperature range of 10 to 60℃: y = a1x + b1, where a1 is in the range of -0.015% to -0.01%, b1 is in the range of 1.5 to 1.6, and has a refractive index of 1.520 to 1.510; and wherein the terpolymer transparent resin is prepared by bulk polymerization of a monomer mixture comprising styrene, methyl methacrylate and acrylonitrile, wherein the amounts of each component are: 50 to 70 parts by weight of methyl methacrylate, 10 to 30 parts by weight of styrene, and 5 to 20 parts by weight of acrylonitrile.

2. A method for preparing the transparent resin as described in claim 1, comprising: a) Mix styrene, methyl methacrylate, acrylonitrile, organic peroxide initiator A, chain transfer agent, and reaction medium to obtain a reaction mixture; wherein, the mixture of styrene, methyl methacrylate, acrylonitrile, and reaction medium is referred to as the "initial raw material and reaction medium mixture"; b) Add the reaction mixture described in a) to reactor 1) to carry out a bulk polymerization reaction. The reaction temperature of reactor 1) is controlled by a gas-phase circulating liquid, wherein the temperature of the gas-phase circulating liquid is 30-40°C and the proportion of reaction medium in the circulating liquid is 15-25%, to obtain a polymer mixture. c) Add the polymerization mixture described in b) and organic peroxide initiator B to reactor 2) to carry out bulk polymerization reaction. The temperature of the gas phase circulating liquid in reactor 2) is 20-30°C, and the proportion of reaction medium in the circulating liquid is 35-45%, to obtain the polymerization mixture. d) After step c) is completed, the polymer mixture is transferred to a devolatilization tank to remove the light components, yielding a transparent copolymer resin.

3. The method according to claim 2, wherein, In step a), the amount of reaction medium used is 10 to 20 parts by weight; In step a), based on 100 parts by weight of the mixture of initial raw materials and reaction medium, the amount of organic peroxide initiator A added is 0.01 to 0.03 parts by weight, and the amount of chain transfer agent added is 0.05 to 0.2 parts by weight.

4. The method according to claim 2 or 3, wherein, The reaction medium is one or more of cyclohexane, toluene, xylene, and ethylbenzene; and / or Initiator A is at least one of 1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane and 1,1-bis(tert-butylperoxy)cyclohexane; and / or The chain transfer agent is a thiol-based compound.

5. The method according to claim 4, wherein, Chain transfer agents include at least one of tert-dodecyl mercaptan and n-octyl mercaptan.

6. The method according to claim 2 or 3, wherein, Step b) The reaction temperature is 130-145℃, and the bulk polymerization conversion rate is 50-55%.

7. The method according to claim 2 or 3, wherein, Step c) The reaction temperature is 145-155℃, and the bulk polymerization conversion rate is 75-80%.

8. The method according to any one of claims 2-3, wherein, In step c), based on 100 parts by weight of the initial raw material and reaction medium mixture, the amount of organic peroxide initiator B added is 0.002 to 0.005 parts by weight.

9. The method according to claim 8, wherein, In step c), initiator B is one or more of cumene peroxide and dicumene peroxide.

10. The method according to any one of claims 2-3, wherein, In step d), the devolatilization temperature is 210–240°C, the absolute pressure is 3–10 kPa, and the devolatilization time is 10–15 min.

11. The use of the transparent resin according to claim 1 in the preparation of transparent ABS resin.

12. A transparent ABS resin comprising the styrene-acrylonitrile-acrylate terpolymer transparent resin of claim 1.

13. The transparent ABS resin according to claim 12, wherein, The content of styrene-acrylonitrile-acrylate terpolymer transparent resin is 50-85%.

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