Manufacturing method of alloy resin

Abstract

To provide an alloy resin of a vinyl chloride resin and a methyl methacrylate resin having excellent transparency, and a method of producing the same.SOLUTION: An alloy resin has a vinyl chloride resin and a methyl methacrylate resin blended in a mass ratio 40:60-90:10 and has a total light transmittance of 50% or more and a haze of 25% or less. An alloy resin production method is to produce an alloy resin by blending a vinyl chloride resin and a methyl methacrylate resin in a mass ratio 40:60-90:10 and using a feedback screw 1 to conduce a shear process under the conditions where the number of rotations of a screw is 100-800 rpm and the resin temperature is 180-220°C.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an alloy resin and a method for producing the same. [Background technology]

[0002] Generally, polypropylene and acrylonitrile-butadiene-styrene (ABS) resins are used as molding resins for injection molded products. These general-purpose resins are excellent in terms of moldability and cost, but tend to have low surface hardness and poor scratch resistance. Acrylic resins and rigid polyvinyl chloride resins are known to have excellent scratch resistance.

[0003] Alloying is known as a method for improving the properties of resins. There are three methods for alloying: 1) mechanical blending using a multi-screw extruder, 2) mixing with a compatibilizer, and 3) reactive processing. Patent Document 1 discloses an alloy resin of a vinyl chloride resin and a methyl methacrylate resin. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 61-014246 Summary of the Invention [Problem to be solved by the invention]

[0005] However, conventional alloy resins such as those described in Patent Document 1 have limitations in fine dispersion and poor transparency, so that their applications are limited.

[0006] An object of the present invention is to provide an alloy resin of vinyl chloride resin and methyl methacrylate resin having excellent transparency, and a method for producing the same. [Means for solving the problem]

[0007] The present invention has the following configuration. [1] An alloy resin in which a polyvinyl chloride resin and a methyl methacrylate resin are blended in a mass ratio of 40:60 to 90:10, and which has a total light transmittance of 50% or more and a haze of 25% or less. [2] The alloy resin according to [1], wherein a mass ratio of the vinyl chloride resin to the methyl methacrylate resin is 40:60 to 70:30. [3] The alloy resin according to [1], wherein the vinyl chloride resin is a rigid vinyl chloride resin. [4] A method for producing an alloy resin, comprising blending a polyvinyl chloride resin and a methyl methacrylate resin in a mass ratio of 40:60 to 90:10, and shearing the mixture using a feedback screw at a screw rotation speed of 100 to 800 rpm and a resin temperature of 180 to 220°C to obtain an alloy resin. Effect of the Invention

[0008] According to the present invention, it is possible to provide an alloy resin of a vinyl chloride resin and a methyl methacrylate resin having excellent transparency, and a method for producing the same. [Brief description of the drawings]

[0009] [Figure 1] FIG. 2 is a front view showing an example of a feedback screw used in the method for producing an alloy resin of the present invention. [Diagram 2] FIG. 2 is a cross-sectional view showing an example of a shearing machine equipped with the feedback screw of FIG. 1. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] [Alloy resin] The alloy resin of the present invention is an alloy resin in which polyvinyl chloride resin (hereinafter referred to as "PVC-based resin") and methyl methacrylate-based resin (hereinafter referred to as "MMA-based resin") are blended in a mass ratio of 40:60 to 90:10, and has a total light transmittance of 50% or more and a haze of 25% or less.

[0011] A PVC-based resin is a polymer in which the proportion of repeating units derived from vinyl chloride (hereinafter also referred to as "vinyl chloride units") exceeds 50% by mass based on the total repeating units. The PVC-based resin may be a homopolymer of vinyl chloride, or a copolymer of vinyl chloride and a vinyl monomer copolymerizable with vinyl chloride. When the PVC-based resin is a copolymer, it may be a random copolymer, a block copolymer, or a graft copolymer. The PVC resin contained in the alloy resin may be one type or two or more types.

[0012] The proportion of vinyl chloride units in the PVC resin is preferably 75 mass % or more, more preferably 80 mass % or more, further preferably 85 mass % or more, and particularly preferably 98 mass % or more, based on all repeating units.

[0013] The vinyl monomer copolymerizable with vinyl chloride is not particularly limited, and examples thereof include fatty acid vinyl esters, acrylates, methacrylates, vinyl cyanide, vinyl ethers, α-olefins, unsaturated carboxylic acids or their acid anhydrides, vinylidene chloride, vinyl bromide, various urethanes, and the like.

[0014] Examples of fatty acid vinyl esters include vinyl acetate, vinyl propionate, and vinyl laurate. Examples of acrylates include methyl acrylate, ethyl acrylate, and butyl acrylate. Examples of methacrylates include methyl methacrylate and ethyl methacrylate. Examples of vinyl cyanides include acrylonitrile and methacrylonitrile. Examples of vinyl ethers include vinyl methyl ether, vinyl butyl ether, and vinyl octyl ether. Examples of α-olefins include ethylene, propylene, and butylene. Examples of unsaturated carboxylic acids or their acid anhydrides include acrylic acid, methacrylic acid, and maleic anhydride. The vinyl monomer copolymerizable with vinyl chloride may be used alone or in combination of two or more.

[0015] The average degree of polymerization of the PVC resin is preferably 400 to 1200, more preferably 500 to 800, and even more preferably 550 to 700. When the average degree of polymerization of the PVC resin is equal to or higher than the lower limit of the above range, the moldability is good. When the average degree of polymerization of the PVC resin is equal to or lower than the upper limit of the above range, the strength is improved. The average degree of polymerization is measured in accordance with JIS K 6720-2.

[0016] The vinyl chloride resin may be either a hard vinyl chloride resin or a soft vinyl chloride resin, but the hard vinyl chloride resin is preferred because it provides a molded product with high surface hardness and excellent scratch resistance.

[0017] The MMA-based resin is a polymer in which the proportion of repeating units derived from methyl methacrylate (MMA) (hereinafter also referred to as "MMA units") is 80 mass% or more based on the total repeating units. The MMA-based resin may be a homopolymer of MMA, or a copolymer of MMA and a (meth)acrylate other than MMA. Note that (meth)acrylate is a general term for methacrylate and acrylate. When the MMA-based resin is a copolymer, it may be a random copolymer or a block copolymer. The MMA resin contained in the alloy resin may be one type or two or more types.

[0018] The proportion of MMA units in the MMA-based resin is preferably 80% by mass or more, more preferably 90% by mass or more, based on all repeating units. When the proportion of MMA units is equal to or more than the lower limit of the above range, moldability is improved.

[0019] Examples of (meth)acrylates other than MMA include methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, 2-ethylhexyl acrylate, ethyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, and 2-ethylhexyl methacrylate. The (meth)acrylate other than MMA used in the MMA-based resin may be one type or two or more types.

[0020] The weight average molecular weight of the MMA resin is preferably 10,000 to 600,000, more preferably 20,000 to 400,000. When the weight average molecular weight of the MMA resin is equal to or higher than the lower limit of the above range, the surface smoothness is good. When the weight average molecular weight of the MMA resin is equal to or lower than the upper limit of the above range, the strength is improved. The weight average molecular weight is the average molecular weight in terms of polystyrene measured by gel permeation chromatography.

[0021] The melt flow rate (MFR) of the MMA resin is preferably 1 to 20 g / 10 min, more preferably 2 to 10 g / 10 min. When the MFR of the MMA resin is equal to or higher than the lower limit of the above range, the processability is good. When the MFR of the MMA resin is equal to or lower than the upper limit of the above range, the generation of burrs in the mold is reduced. The MFR is measured in accordance with JIS K 7210 under conditions of a load of 37.3 N and a temperature of 230°C.

[0022] The mass ratio of the PVC resin to the MMA resin is 40:60 to 90:10, preferably 40:60 to 80:20, and more preferably 40:60 to 70:30. The higher the proportion of the PVC resin, the higher the strength. The higher the proportion of the MMA resin, the higher the hardness.

[0023] The total proportion of the PVC resin and the MMA resin in the alloy resin is preferably 80 mass % or more, more preferably 85 mass % or more, and even more preferably 90 mass % or more, based on the total mass of the alloy resin.

[0024] Additives such as a heat stabilizer, a light stabilizer, a lubricant, etc. may be added to the alloy resin of the present invention as required, so long as the effect of the present invention is not impaired. The form of the alloy resin of the present invention is not particularly limited, and may be, for example, in the form of pellets.

[0025] The alloy resin of the present invention has a total light transmittance of 50% or more, preferably 70% or more, and more preferably 80% or more. When the total light transmittance is equal to or more than the lower limit, the transparency is excellent. The total light transmittance of the alloy resin is measured in accordance with JIS K7361.

[0026] The haze of the alloy resin of the present invention is 25% or less, preferably 10% or less, and more preferably 5% or less. When the haze is equal to or less than the upper limit, the transparency is excellent. The haze of the alloy resin is measured in accordance with JIS K7361.

[0027] The pencil hardness of the alloy resin of the present invention is preferably HB or more, and more preferably H or more. When the pencil hardness is equal to or more than the lower limit, the molded product has excellent scratch resistance. The pencil hardness of the alloy resin is measured in accordance with JIS K5600-5-4.

[0028] The alloy resin of the present invention described above has a high total light transmittance, a controlled low haze, and excellent transparency. The applications of the alloy resin of the present invention are not particularly limited, and it can be used, for example, in injection molded articles used in vehicles, building materials, home appliances, and the like.

[0029] [Manufacturing method of alloy resin] The method for producing an alloy resin of the present invention is a method for obtaining an alloy resin by blending a PVC resin and an MMA resin in a mass ratio of 40:60 to 90:10, and shearing the mixture using a feedback screw at a screw rotation speed of 100 to 800 rpm and a resin temperature of 180 to 220° C. According to the production method of the present invention, an alloy resin whose total light transmittance and haze satisfy the above-mentioned ranges can be obtained.

[0030] An example of a feedback screw and a shearing machine equipped with a feedback screw will be described with reference to Figs. 1 and 2. In addition, the dimensions of the figures illustrated in the following description are merely examples, and the present invention is not necessarily limited to them, and can be implemented with appropriate modifications within the scope that does not change the gist of the present invention.

[0031] As shown in Fig. 1, the feedback screw 1 includes a cylindrical screw body 10 and a protrusion 12 having a rectangular cross section that is spirally provided on the outer peripheral surface of the screw body 10. The screw body 10 is formed with a feedback hole 14 having a circular cross section that extends partway from the tip 10a to the rear end 10b along the central axis m and leads to the outer peripheral surface of the screw body 10. The feedback screw 1 is an internal feedback screw.

[0032] The length L of the screw body 10 is not particularly limited and can be, for example, 40 to 300 mm. The outer diameter D of the screw body 10 is not particularly limited and can be, for example, 10 to 100 mm.

[0033] The height H of the ridges 12 is not particularly limited and can be, for example, 1 to 20 mm. The flight pitch P of the ridges 12 is not particularly limited and can be, for example, 5 to 50 mm.

[0034] The diameter d of the return hole 14 is not particularly limited and can be, for example, 1 to 5 mm. The length L1 of the return hole 14 is not particularly limited, and can be, for example, 30 to 250 mm.

[0035] 2, the shear processing machine 100 includes a pre-plasticizing section 110 and a shear processing section 120. The tip of the pre-plasticizing section 110 is connected to the side of the shear processing section 120. A single screw 112 is provided inside the pre-plasticizing section 110. A feedback screw 1 is provided inside the shear processing section 120. A discharge port 122 is formed on the tip 10a side of the feedback screw 1 in the shear processing section 120. The driving method of the single screw 112 of the pre-plasticizing section 110 and the feedback screw 1 of the shear processing section 120 is not particularly limited, and may be, for example, a servo motor.

[0036] In the shear processing machine 100, resin is supplied to the pre-plasticization section 110, and while the resin is plasticized by the single screw 112, it is pumped toward the shear processing section 120. In the shear processing section 120, the feedback screw 1 rotates around the central axis m, and while the resin is pumped from the rear end 10b to the front end 10a on the outside of the screw body 10 by the movement of the protrusion 12, the resin returns from the front end 10a to the rear end 10b through the return hole 14, and the resin circulates. This repeats shearing and elongation, achieving nano-dispersion and mixing.

[0037] The screw rotation speed of the feedback screw during shear processing is 100 to 800 rpm, preferably 150 to 700 rpm, and more preferably 200 to 600 rpm. If the screw rotation speed is equal to or higher than the lower limit of the above range, the transparency is improved. If the screw rotation speed is equal to or lower than the upper limit of the above range, the hardness is improved.

[0038] The resin temperature during shear processing by the feedback screw is 180 to 220° C., and more preferably 190 to 210° C. If the resin temperature during shear processing is equal to or higher than the lower limit of the above range, the strength is improved. If the resin temperature during shear processing is equal to or lower than the upper limit of the above range, the thermal stability is good.

[0039] The shear rate during shear processing is 150 to 1200 s -1 is preferable, 230 to 1000s -1 More preferably, 300 to 900s -1 When the shear rate is equal to or higher than the lower limit of the above range, the processability is good, and when the shear rate is equal to or lower than the upper limit of the above range, the dispersibility is good.

[0040] The processing time by the feedback screw can be appropriately set and can be, for example, 1 to 30 seconds.

[0041] The alloying of different polymers is influenced by the compatibility of each polymer. If the polymers have good compatibility, the dispersed polymers will be more likely to mix together. PVC-based resins and MMA-based resins are classified as semi-compatible, so it is difficult to achieve fine dispersion at the nano level using conventional alloying methods.

[0042] In the present invention, a feedback screw is used, and the screw rotation speed and resin temperature of the feedback screw are controlled within a specific range to perform shear processing (kneading), thereby making it possible to finely disperse the PVC-based resin and the MMA-based resin. Therefore, even without using a compatibilizer, an alloy resin of PVC-based resin and MMA-based resin with excellent transparency can be obtained. In addition, the alloy resin obtained by the manufacturing method of the present invention has high surface hardness and excellent scratch resistance.

[0043] The manufacturing method of the present invention is not limited to the method using the feedback screw 1 illustrated in FIG. 1 or the shear processing machine 100 illustrated in FIG. 2, as long as it uses a feedback screw and controls the screw rotation speed and resin temperature within the specific ranges described above. EXAMPLES

[0044] The present invention will be specifically described below with reference to examples, but the present invention is not limited to the following description. [Total light transmittance, haze] The total light transmittance and haze were measured in accordance with JIS K7361.

[0045] [Pencil hardness] The pencil hardness was measured in accordance with JIS K5600-5-4.

[0046] [Example 1] 90 parts by mass of TJX-2159 (trade name, manufactured by Shin-Etsu Polymer Co., Ltd., proportion of vinyl chloride units: 91 mass%, average degree of polymerization: 600) as a PVC-based resin and 10 parts by mass of Delpet 80N (trade name, manufactured by Asahi Kasei Corporation, proportion of MMA units: 95 mass%, weight average molecular weight: 100,000, MFR: 2 g / 10 min) as an MMA-based resin were sheared by a shearing machine 100 equipped with a feedback screw 1 as illustrated in Figs. 1 and 2 to obtain an alloy resin. The feedback screw 1 had a length L of the screw body 10 of 50 mm, an outer diameter D of the screw body 10 of 28 mm, a flight pitch P of the protrusions 12 of 11 mm, a height H of the protrusions 12 of 2 mm, a diameter d of the return hole 14 of 2.5 mm, and a length L1 of the return hole 14 of 40 mm. The conditions for shear processing were a screw rotation speed of 200 rpm, a resin temperature during shear processing of 200°C, and a shear rate of 300 s -1 The resin temperature during shear processing was measured by an infrared temperature sensor. The obtained alloy resin was hot pressed at 190° C. to form a resin plate of length 120 mm × width 120 mm × thickness 4 mm, which was used for each evaluation test.

[0047] [Examples 2 to 6] Except for changing the amounts of PVC-based resin and MMA-based resin used and the screw rotation speed as shown in Table 1, alloy resins were produced in the same manner as in Example 1, and resin plates were prepared and used in each evaluation test.

[0048] [Comparative Example 1] 70 parts by mass of TJX-2159 (trade name, manufactured by Shin-Etsu Polymer Co., Ltd., vinyl chloride unit ratio: 91% by mass, average polymerization degree: 600) as a PVC-based resin and 30 parts by mass of Delpet 80N (trade name, manufactured by Asahi Kasei Co., Ltd., MMA unit ratio: 95% by mass, weight average molecular weight: 100,000, MFR: 2 g / 10 min) as an MMA-based resin were injection molded using an injection molding machine (trade name J110AD, manufactured by JSW Co., Ltd.) equipped with a single screw, and a resin plate measuring 120 mm in length, 75 mm in width, and 3 mm in thickness was prepared and used for each evaluation test. The screw rotation speed during injection molding was 50 rpm, the resin temperature was 190 °C, and the shear rate was 60 s -1 It was decided.

[0049] [Comparative Example 2] 70 parts by mass of TJX-2157 (trade name, manufactured by Shin-Etsu Polymer Co., Ltd., vinyl chloride unit ratio: 88% by mass, average polymerization degree: 700) as a PVC-based resin and 30 parts by mass of Delpet 80N (trade name, manufactured by Asahi Kasei Co., Ltd., MMA unit ratio: 95% by mass, MFR: 2 g / 10 min) as an MMA-based resin were mixed at a screw rotation speed of 50 rpm, a resin temperature during shear processing of 190 °C, and a shear rate of 75 s -1 The mixture was sheared by a shearing machine 100 equipped with a feedback screw 1 in the same manner as in Example 1, except that the above-mentioned conditions were met to obtain an alloy resin. The obtained alloy resin was hot pressed at 190° C. to form a resin plate of length 120 mm × width 120 mm × thickness 4 mm, which was used for each evaluation test.

[0050] [Comparative Examples 3 to 4] Except for changing the amounts of PVC-based resin and MMA-based resin used as shown in Table 2, resin plates were prepared in the same manner as in Comparative Example 1 and used in each evaluation test.

[0051] [Reference example 1] A resin plate was prepared in the same manner as in Comparative Example 1, except that 100 parts by mass of TJX-2157 (product name, manufactured by Shin-Etsu Polymer Co., Ltd., proportion of vinyl chloride units: 88% by mass, average degree of polymerization: 700) was used as the PVC-based resin and no MMA-based resin was used, and was used in each evaluation test.

[0052] [Reference example 2] A resin plate was prepared in the same manner as in Comparative Example 1, except that 100 parts by mass of Delpet 80N (product name, manufactured by Asahi Kasei Corporation, proportion of MMA units: 95 mass%, weight average molecular weight: 100,000, MFR: 2 g / 10 min) was used as the MMA resin and no PVC resin was used, and was used in each evaluation test.

[0053] The production conditions and evaluation results of each example are shown in Tables 1 and 2.

[0054] [Table 1]

[0055] [Table 2]

[0056] As shown in Tables 1 and 2, the alloy resins of Examples 1 to 6, which were produced using a feedback screw to satisfy specific conditions, had high total light transmittance, low haze, and excellent transparency. The alloy resins of Examples 1 to 6 also had low haze and excellent transparency compared to the PVC resin alone of Reference Example 1 and the MMA resin alone of Reference Example 2. Furthermore, the alloy resins of Examples 1 to 6 had high pencil hardness and excellent scratch resistance. On the other hand, the alloy resins of Comparative Examples 1 and 3, which were made using a conventional injection molding machine, and Comparative Example 2, which had a low screw rotation speed of the feedback screw, had low total light transmittance, high haze, and poor transparency. [Explanation of symbols]

[0057] 1...feedback screw, 10...screw body, 12...protrusion, 14...feedback hole, 100...shear processing machine, 110...pre-plasticization section, 120...shear processing section.

Claims

[Claim 1] A method for producing an alloy resin, comprising blending a vinyl chloride resin and a methyl methacrylate resin, and shearing the blend using a feedback screw at a screw rotation speed of 100 to 800 rpm and a resin temperature of 180 to 220° C. to obtain an alloy resin, A method for producing an alloy resin, comprising blending a vinyl chloride resin and a methyl methacrylate resin in a mass ratio of 40:60 to 90:10.

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