Method for kneading chlorine-based resin compositions

Abstract

To provide a method for kneading a chlorine-based resin composition using an internal kneader, and a technique capable of kneading a material without increasing a filling rate of the material in an effective volume of a kneading tank.SOLUTION: There is provided a method for kneading a chlorine-based resin composition using an internal kneader equipped with a kneading tank, having a step of kneading a material containing a chlorine-based resin composition composed of a vinyl chloride resin (A), a plasticizer (B), a chlorinated polyethylene (C), and a stabilizer (D). The compositions of (A) to (D), based on a total of 100 pts.mass of the material, are (A) / (B) / (C) / (D)=15 to 75 / 5 to 40 / 5 to 65 / 5 to 15, respectively, and a filling rate of the material with respect to an effective volume of the kneading tank of the internal kneader is 50% or less.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a method for kneading a chlorine-based resin composition using a closed kneader.

Background Art

[0002] Chlorine-based resin compositions typified by soft vinyl chloride resin (PVC) are used, for example, as coating materials for electric wires, window frames, hoses, or films.

[0003] The manufacturing method proceeds in the order of a blending step of weighing and mixing vinyl chloride resin, plasticizer, stabilizer, filler, flame retardant, etc., a kneading step of kneading the blended material, and a granulation step of granulating the kneaded material. The important step here is the kneading step, and as the apparatus, a closed kneader such as a single-screw kneading extruder or a twin-screw kneading extruder is used.

[0004] Patent Document 1 (Japanese Patent Application Laid-Open No. 2019-84789) describes a closed kneader equipped with two rotors.

[0005] On the other hand, in the blending step, the property of the raw material vinyl chloride resin is powder, which is mixed with a liquid plasticizer to become viscous. By proceeding with the mixing step under heating conditions, it is known that the vinyl chloride resin absorbs the plasticizer and changes back to a non-viscous powder state. This change is called dry-up. Even if a material with insufficient dry-up is kneaded, a soft vinyl chloride resin with good dispersibility cannot be obtained, so the blending step is also important following the kneading step.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] For kneading dried, flexible polyvinyl chloride resin, single-screw and twin-screw extruders capable of constant volume supply offer superior production efficiency. Furthermore, closed-type kneaders have the advantage of allowing for flexible kneading time and are suitable for kneading special flexible polyvinyl chloride resin materials. However, closed-type kneaders have the drawback that kneading will not proceed unless the material filling rate relative to the effective volume of the kneading tank is increased to create a pressurized environment.

[0008] Therefore, the present invention aims to provide a kneading method for kneading a chlorine-based resin composition using a closed-type kneader, which enables kneading without increasing the material filling rate in the effective volume of the kneading tank. [Means for solving the problem]

[0009] [1] A method for kneading a chlorine-based resin composition according to one aspect of the present invention is a method for kneading a chlorine-based resin composition using a closed-type kneader equipped with a kneading tank, comprising the step of kneading a material containing a chlorine-based resin composition composed of vinyl chloride resin (A), a plasticizer (B), chlorinated polyethylene (C), and a stabilizer (D), wherein the compositions of (A) to (D) are (A) / (B) / (C) / (D) = 15 to 75 / 5 to 40 / 5 to 65 / 5 to 15, respectively, with respect to 100 parts by mass of the total material, and the filling rate of the material with respect to the effective volume of the kneading tank of the closed-type kneader being 50% or less.

[0010] In [2][1], the kneading is performed by adding calcined clay, titanium dioxide, or trimethylolpropane acrylate as a filler or additive to the material.

[0011] In [3][2], antimony trioxide, a metal hydrate, or a brominated flame retardant is added to the material as a flame retardant and the kneading is performed.

[0012] In [4][1] or [3], after kneading, one or more of the following are added to the material to produce a polymer alloy: acrylic resin, nitrile butyl rubber, ethylene vinyl acetate copolymer, polyurethane thermoplastic elastomer, polyester polymer, methyl methacrylate-butadiene-styrene copolymer, or acrylonitrile-butadiene-styrene resin. [Effects of the Invention]

[0013] According to one embodiment of the present invention, a kneading method for kneading a chlorine-based resin composition using a closed-type kneader provides a technique that allows kneading without increasing the material filling rate in the effective volume of the kneading tank. [Brief explanation of the drawing]

[0014] [Figure 1] This is a cross-sectional view of a closed-type kneader during the kneading process in the embodiment. [Figure 2] This is a cross-sectional view of a closed-type kneader during the kneading process in the embodiment. [Figure 3] This is a cross-sectional view of a closed-type kneader during the kneading process in the embodiment of Comparative Example 1. [Figure 4] This is a cross-sectional view of a closed-type kneader during the kneading process in the embodiment of Comparative Example 1. [Modes for carrying out the invention]

[0015] (Embodiment) Figures 3 and 4 show cross-sectional views of a closed-type kneader during the kneading process in Comparative Example 1. As shown in Figures 3 and 4, the closed-type kneader 1 comprises a kneading tank 2, a pressure lid 3 positioned above the kneading tank 2 and movable vertically, and two rotors 4 provided in the space within the kneading tank 2 and rotating on an axis. When the pressure lid 3 is moved downward after the material to be kneaded 6 is introduced into the kneading tank 2, the opening of the kneading tank 2 is closed and the material 6 inside the kneading tank 2 is pressurized. The material 6 consists of components such as polyvinyl chloride resin, plasticizers, and other stabilizers.

[0016] Each of the two rotors 4 rotates (swivels) in the kneading tank 2 with the axis along the depth direction of FIGS. 3 and 4 as the rotation axis. Due to such rotation of the rotor 4, a dispersion flow, a distribution flow, and an elongation flow of the material 6 are generated in the kneading tank 2, and the material 6 is kneaded.

[0017] There is a problem with the closed kneader that kneading does not proceed unless the filling rate of the material with respect to the effective volume of the kneading tank is increased to make the inside in a pressurized state. That is, as shown in FIG. 3, it is difficult to knead the material 6 when the filling degree of the material 6 in the kneading tank 2 is low. In FIG. 3, the filling rate of the material 6 with respect to the effective volume of the kneading tank of the closed kneader 1 is 50% or less.

[0018] On the other hand, as shown in FIG. 4, if the filling degree of the material 6 in the kneading tank 2 is increased and the pressure lid 3 is moved downward to pressurize the inside of the kneading tank 2, the material 6 can be kneaded. However, in such a kneading method of increasing the filling rate of the material with respect to the effective volume of the kneading tank in the kneading tank 2 and pressurizing the inside of the kneading tank 2, there is a problem that it is difficult to reduce the production amount per batch of the closed kneader.

[0019] Hereinafter, specific materials and examples used in the kneading method of the present embodiment will be described.

[0020] [Examples] Hereinafter, examples of the present embodiment will be described using FIGS. 1, FIGS. 2, and Tables 1 to 4.

[0021] (Materials) In Examples 1 to 4 of the present embodiment, the raw materials used are as shown in Table 1. In addition, Table 1 shows, as Comparative Example 1, a case where a vinyl chloride resin composition is kneaded using a closed kneader, different from the present embodiment. That is, Comparative Example 1 kneads in a three-component system of vinyl chloride resin, plasticizer, and other stabilizers.

[0022] Furthermore, to demonstrate the feasibility of polymer alloy compounding, compounding is performed by alloying ester-based TPU with the material from Example 1, as shown in Table 4. That is, as shown in Figure 2, TPU is added to material 5 in a closed-type compounder 1 and compounding is performed further. In Figure 2, the added TPU is indicated by a black square.

[0023] (Low-fill mixing using a closed-type mixer) To confirm the low-filling kneading performance using a closed-type hot kneader, the experiment was conducted under the following conditions. Specifically, the raw materials with the composition ratios shown in Table 1 were weighed and added as shown in Table 1. The kneading conditions were a chamber temperature of 160°C and a rotor speed of 30 rpm.

[0024] [Table 1]

[0025] The material names shown in Table 1 are as follows: 1) Polymer A: Taiyo Vinyl Chloride Co., Ltd. "TH-1700" 2) Plasticizer B: TOTM 3) Polymer C: "Elastren 352GB-X5" manufactured by Showa Denko Corporation. 4) Stabilizer D: "HT-1" manufactured by Sakai Chemical Industry Co., Ltd. 5) Stabilizer D: "OW3152" manufactured by Sakai Chemical Industry Co., Ltd. 6) Flame retardant: "BF-013" (aluminum hydroxide) manufactured by Nippon Light Metal Co., Ltd. 7) Flame retardant: "Scitex 8010" (brominated flame retardant) manufactured by Albemarle Japan Co., Ltd. 8) Flame retardant: "NANO-200" (antimony trioxide) manufactured in Chenzhou, China. 9) Coloring agent: "R820" manufactured by Ishihara Sangyo Co., Ltd. (Titanium White: Titanium Oxide) 10) Filler and strengthening agent: BASF "Cast Clay #33" 11) Additive: Manufactured by Shin-Nakamura Chemical Industry Co., Ltd. (TMPT: Trimethylolpropane Acrylate) (Determination of whether mixing is possible) The mixture was kneaded for 10 minutes under the aforementioned conditions, and the mixing state was first checked. Any mixture that remained in powder form was deemed unsatisfactory. For mixtures that gelled and remained continuous, the kneaded mass was taken and its dispersion form was checked as follows.

[0026] A 5g sample of the kneaded mass was taken and thinned using a pressure press. Samples that did not show filler aggregation or fish-eye formation due to polyvinyl chloride resin were considered good. The pressure pressing conditions were as follows: preheating to 180°C for 3 minutes, pressurizing to 10 MPa for 2 minutes, and then cooling to room temperature over 5 minutes.

[0027] Table 3 shows the results of the judgment regarding the feasibility of mixing. Examples 1 to 4, as shown in Table 2, were mixed by reducing the material occupancy rate relative to the effective volume of the mixing tank of a closed-type mixer to 15-30%, and good results were obtained. In contrast, in Comparative Example 1, no cohesive formation (gelation) occurred and mixing did not proceed in any case of occupancy rates of 45%, 40%, and 30%. Table 2 shows the batch amount (unit: g) as a result of mixing experiments using a closed-type mixer with a volume of 6 liters. Table 3 shows the results of mixing low batch amounts.

[0028] [Table 2]

[0029] [Table 3]

[0030] Next, a demonstration test of the polymer alloy was conducted using the composition ratios shown in Table 4. After confirming the mixing state of Example 1, which had been kneaded for 10 minutes, TPU was added, and the dispersion form was confirmed after further kneading for 10 minutes under the kneading conditions described above in "Materials" and "Low-fill kneading using a closed-type kneader". The values ​​corresponding to the TPU column in Example 1 of Table 4 indicate the batch amount, as in Table 2. The same method as described above was used to confirm the dispersion form in "Determination of kneadability". Note that "TPU P25MRWJE" shown in Table 4 is an ester-based TPU manufactured by Nippon Miractran Co., Ltd.

[0031] [Table 4]

[0032] Table 4 shows the results of the polymer alloy validation tests. Good results were obtained as shown in Examples 5 to 7. Of particular note is the good dispersion under the conditions of Example 7 (material filling rate relative to the effective volume of the mixing tank (hereinafter referred to as volume filling rate) of 47%). This confirmed the effectiveness of this composition and mixing method.

[0033] <Effects of this embodiment> As described above with reference to Comparative Example 1 using Figure 3, when using the closed-type kneader 1, if the material to be kneaded is, for example, a polyvinyl chloride resin composition and the volume occupancy rate is low, kneading will not proceed. As a way to advance the kneading, as shown in Figure 4, a method of increasing the volume occupancy rate and pressurizing with the pressure lid 3 can be considered. However, a kneading method that increases the occupancy rate of the kneading tank 2 and pressurizes the kneading tank 2 presents the challenge of making it difficult to reduce the production volume per batch of the closed-type kneader.

[0034] In a three-component mixture of polyvinyl chloride resin, chlorinated polyethylene, and plasticizer, the liquid plasticizer transforms into a viscous dry-up material via a viscous powder. However, producing a completely dry-up material, such as a chlorinated resin composition composed of polyvinyl chloride resin, plasticizer, and other additives, is difficult as long as chlorinated polyethylene is used.

[0035] The inventors hypothesized that this incomplete state would create resistance to movement within the closed-type kneader, thus promoting distribution and mixing. Therefore, the inventors investigated a material composition that would allow mixing to proceed without increasing the material's filling rate within the effective volume of the kneading tank. Specifically, this method involves introducing polyvinyl chloride resin, plasticizers, chlorinated polyethylene (CPE), stabilizers, flame retardants, and fillers, etc., into a closed-type kneader in a low-fill state and then mixing them together.

[0036] Specifically, the material 5 to be kneaded in this embodiment consists of polyvinyl chloride resin (A), plasticizer (B), chlorinated polyethylene (C), and stabilizer (D). The compositions of (A) to (D) are chlorine-based resin compositions such that (A) / (B) / (C) / (D) = 10 to 85 / 1 to 50 / 5 to 70 / 1 to 20, respectively, per 100 parts by mass of the total.

[0037] By using such material 5, as shown in Figure 1, mixing becomes possible even when the material 5 fills 50% or less of the effective volume of the mixing tank of the closed-type mixer 1. Furthermore, mixing of material 5 becomes possible without pressurization. Figure 1 is a cross-sectional view of the closed-type mixer during the mixing process in this embodiment. The closed-type mixer 1 shown in Figure 1 has the same configuration as the closed-type mixer 1 described using Figure 3. The effect of this embodiment is that the production volume per batch of the closed-type mixer can be reduced. In other words, because mixing is possible even when the volume fill rate is low, it leads to a reduction in the batch size per operation, resulting in the advantage of enabling small-lot production.

[0038] Furthermore, it is possible to improve the performance of the materials. In other words, the options for polymer alloys to improve performance increase. This means that polymer alloys can be easily manufactured to compensate for the shortcomings of the previously prepared chlorine-based resin composition. Here, as a specific example, Examples 5 to 7, in which TPU is blended to exhibit wear resistance, are shown in Table 4.

[0039] Specifically, alloying is possible by adding and mixing a polymer different from the main system at the stage when mixing in a low-fill state is completed or in progress. Examples of polymers different from the main system include acrylic resin, NBR (nitrile butyl rubber), EVA (ethylene vinyl acetate copolymer), TPU (polyurethane thermoplastic elastomer), TPEE (polyester polymer), MBS (methyl methacrylate-butadiene-styrene copolymer), and ABS (acrylonitrile-butadiene-styrene resin). Multiple types of these polymers can be selected and mixed, and additives can be added as needed.

[0040] The polymer alloy produced using this method can be used for electrical cable sheathing, window frames, hoses, films, and the like.

[0041] The present invention is not limited to the embodiments and examples described above, and can be modified in various ways without departing from its spirit. [Explanation of symbols]

[0042] 1. Closed-type kneader 2. Mixing tank 3. Pressure lid 4 rotors 5, 6 Materials

Claims

1. A method for kneading a chlorine-based resin composition using a closed-type kneader equipped with a kneading tank, The process includes a step of kneading a material containing a chlorine-based resin composition consisting of polyvinyl chloride resin (A), a plasticizer (B), chlorinated polyethylene (C), and a stabilizer (D). The compositions of (A) to (D) are such that, with respect to 100 parts by mass of the total material, (A) / (B) / (C) / (D) = 15 to 75 / 5 to 20.8 / 5 to 65 / 5 to 15 respectively. A method for kneading a chlorine-based resin composition, wherein the filling rate of the material relative to the effective volume of the kneading tank of the sealed kneader is 50% or less.

2. In the kneading method for the chlorine-based resin composition described in claim 1, A method for kneading a chlorine-based resin composition, wherein, after the kneading, one or more of the following are added to the material to produce a polymer alloy: acrylic resin, nitrile butyl rubber, ethylene vinyl acetate copolymer, polyurethane thermoplastic elastomer, polyester polymer, methyl methacrylate-butadiene-styrene copolymer, or acrylonitrile-butadiene-styrene resin.

3. In the kneading method for the chlorine-based resin composition described in claim 2, A method for kneading a chlorine-based resin composition, comprising adding one or more of the following as flame retardants to the aforementioned material: antimony trioxide, metal hydrate, or bromine-based flame retardant, and then performing the kneading.

4. In a method for kneading a chlorine-based resin composition according to claim 1 or 3, A method for kneading a chlorine-based resin composition, comprising adding calcined clay, titanium dioxide, or trimethylolpropane acrylate as a filler or additive to the aforementioned material and performing the kneading.

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