JP4480447B2 - A method for producing a recycled thermoplastic resin composition. - Google Patents

Description

The present invention relates to recycling of thermoplastic resin wall covering waste, and more particularly to a method for producing a recycled thermoplastic resin composition that is easy to reuse.

In recent years, the demand for recycling of thermoplastic resin products has become stronger, and the recycling of wall coverings is also being studied. In order to recycle, it is necessary to grind the waste material. Usually, the screen mesh of the grinder is set to 20 mmφ or more in consideration of efficiency. In this case, many fibers of the backing paper remained in the pulverized material, and the calendering machine and the extrusion molding machine were poor in formability and difficult to form into a sheet. Several proposals have been made to improve this.

For example, Patent Document 1 discloses a method for pulverizing and separating wallpaper composed of a base paper layer and a resin-impregnated paper layer, and a pulverized product of the resin-impregnated paper layer separated from the base paper layer can be used as a heat insulating layer. Although described, the pulverized product of the resin-impregnated paper layer obtained by this method contains a large amount of paper fibers, and thus is not suitable for calendar molding and extrusion molding.

Although different from the wall covering material, Patent Document 2 discloses a method of recovering a metal component and a resin component from a wire harness, but even if this method is applied to a wall covering material, a step of dissolving in a solvent, It consists of a step of separating insoluble components such as fibers and a step of fractionating the solvent to recover the resin component, resulting in high equipment costs and running costs.

Further, in Patent Document 3 proposed by the present inventors, the residual fiber content remaining in the wall covering material pulverized material is 20% by weight or less, and the fiber content exceeding 15 mm in length is 30% by weight in the residual fiber. % Or less improved the adverse effect of processability due to the fiber content.
However, since wall covering materials are usually foamed products and chemical foaming agents are used, when the wall covering material pulverized material is processed, the undegraded products and / or residues of the chemical foaming agents become bubbles during processing. The condition worsened, and some products were problematic.

JP 05-247863 A JP-A-11-181146 JP 2003-53728 A

The present invention solves the above problems, processes at low cost and efficiently waste materials A, further, good processability, surface state which may calendering, reproduction thermoplastic resin composition which can be applied to extrusion molding (hereinafter, the composition C)).

When the waste material A is reused, the waste material A is pulverized and then heat-treated by stirring at a high temperature of 130 ° C. or higher to remove volatile components, and granulated by a cooling mixer. This is also applicable to the above-mentioned case, and is a production method of the composition C in which a modifier is added during heat treatment.

In the present invention, since the waste material A is pulverized and heat-treated at a temperature of 130 ° C. or higher, the moisture contained in the backing paper of the waste material A or the chemical foaming agent contained when the waste material A is a foamed product is not decomposed. Since an object and / or a residue can be removed, the composition C obtained has good processability and surface condition. Further, the granulation improves the handling property and can prevent moisture reabsorption by the backing paper fibers. Furthermore, the workability and heat resistance of the composition C are improved by adding a modifier during the heat treatment.

Hereinafter, preferred embodiments of the present invention will be described in detail. In the present invention, when recycling the waste material A, after the waste material A is pulverized, it is heat-treated by stirring at a high speed at a temperature of 130 ° C. or higher to remove volatile components, and the production method of the composition C is granulated by a cooling mixer It is.

The present invention can be applied to both non-foamed and foamed types of thermoplastic resin wall coverings, such as vinyl chloride resins, olefin resins such as polyethylene, EVA, EEA, chlorinated polyethylene, polyester resins, (meta ) Applicable to wall covering waste materials composed of thermoplastic resins such as acrylic resins and thermoplastic elastomers (olefin-based, styrene-based, urethane-based, polyester-based). Of these, application to vinyl chloride resins, olefin resins, and thermoplastic elastomers is preferred in terms of ease of use of recycled materials.
In addition, additives such as plasticizers, stabilizers, chelators, fillers, foaming agents, foaming aids, UV absorbers, colorants, flame retardants, antioxidants, processing aids, lubricants, etc. in waste material A There is no problem even if it is added.

In the present invention, as a method for pulverizing the waste material A, a general pulverizer including a fixed blade, a rotary blade, and a screen can be used. When the wall covering material waste is put into the crusher inlet, the wall covering waste material is crushed between the fixed blade and the rotary blade, and the crushed material is discharged through the mesh of the screen. The particle diameter of the pulverized material is determined by the mesh diameter of the screen. In consideration of workability such as calender molding and extrusion molding, and the efficiency of pulverization, the mesh aperture of the screen is preferably 1 to 15 mm, and more preferably 2 to 10 mm. If the mesh diameter of the screen is less than 1 mm, the efficiency is deteriorated, and if it exceeds 15 mm, the workability may be deteriorated.
In addition, although not efficient, fine pulverizers such as freeze pulverization and turbo mill can also be applied.

In the present invention, the pulverized material of the waste material A (hereinafter referred to as pulverized material B) obtained by the above method is heat-treated at a temperature of 130 ° C. or more and granulated. it is possible to get much granular material. Granulation may be performed in a separate step after the heat treatment, or the heat treatment and the granulation step may be performed in-line. In view of efficiency, it is preferable to perform the latter inline.
As a method of heat treatment and granulation, there is a method of heating and mixing the pulverized material B by high-speed stirring with a super mixer, a Henschel mixer, etc., and discharging to a cooling mixer for granulation .

Upper Symbol super mixer, to do the like in heat treatment Henschel mixer, it is necessary to set the set temperature of the device above 130 ° C., and preferably 0.99 ° C. or higher. When the pulverized material B is heat-treated at a set temperature of 130 ° C. or higher, the resin temperature becomes 10-30 ° C. higher than the set temperature due to shear heat generation, and the thermoplastic resin content of the pulverized material B and the backing paper are kneaded or mixed uniformly. become. Furthermore, moisture contained in the fiber of the backing paper and volatile components such as undecomposed products and / or residues of the chemical foaming agent contained in the thermoplastic resin component when the pulverized material B is of the foaming type can be removed at the same time. In the heat treatment at a set temperature of less than 130 ° C., the mixing uniformity of the thermoplastic resin and the backing paper and the removal of volatile components are insufficient, and recycling becomes difficult.

In the present invention, it is preferable to add a modifier during the heat treatment, and the processability and heat resistance of the composition C can be improved by adding the modifier. Examples of the modifier include plasticizers, stabilizers, antioxidants, chelators, UV absorbers, lubricants, processing aids, fillers, etc. Among them, plasticizers, stabilizers, antioxidants, lubricants, processing aids. Agents are preferred. These modifiers may be used alone or in combination of two or more.

Examples of the plasticizer include phthalic acid esters such as DOP, DINP, and DIDP, aliphatic dibasic acid esters such as DOA, DIDA, DOS, and DOZ, phosphoric acid esters such as TCP, CDP, and TXP; Mellitic acid esters, chlorinated paraffins, polyester plasticizers, epoxy plasticizers and the like can be mentioned, and these are used alone or in combination. The addition amount of the plasticizer is preferably 1 to 50% by weight, and preferably 2 to 30% by weight with respect to the pulverized material B.

Examples of the stabilizer include metal soaps such as barium stearate, organotin stabilizers such as tin laurate, phosphite stabilizers such as tetraphenyl polypropylene glycol diphosphite, and perchloric acid-treated hydrotalcite. Hydrotalcite-based stabilizers such as are used, and are used alone or in combination. The addition amount of the stabilizer is preferably 0.1 to 5% by weight, and preferably 0.2 to 3% by weight with respect to the pulverized material B.

Examples of the antioxidant include phenols such as 2,2′-methylene-bis- (4-methyl-6-tert-butylphenol), phosphites such as trisnonylphenyl phosphite, and ditridecyl-3,3. Sulfur-based compounds such as' -thiodipropionate can be mentioned and used alone or in combination. As addition amount of antioxidant, 0.01-3 weight% is good with respect to the pulverized material B, and 0.22-2 weight% is preferable.

Examples of the lubricant include fatty acid ester waxes such as n-butyl stearate, hydrocarbon waxes, fatty acids such as stearic acid and lauric acid, fatty alcohols such as stearyl alcohol, amides such as methylenebisstearylamide, stearin Metal soaps such as magnesium acid and zinc stearate, polyethylene wax, natural wax and the like can be mentioned, and these are used alone or in combination. The addition amount of the lubricant is preferably 0.1 to 3% by weight, and preferably 0.2 to 1% by weight with respect to the pulverized material B.

Examples of the processing aid include methyl methacrylate-alkyl acrylate copolymers such as methyl methacrylate-butyl acrylate copolymer, which are used alone or in combination. . The addition amount of the processing aid is preferably 0.2 to 10% by weight, and preferably 0.5 to 5% by weight with respect to the pulverized material B.

By granulating following the heat treatment, the composition C has improved handling properties, and the fibers of the backing paper are uniformly mixed with the thermoplastic resin component, so that reabsorption of moisture by the fibers can also be prevented.

Thus, since the manufacturing method of the present invention for obtaining the composition C can use ordinary equipment without requiring special equipment, the waste material A can be recycled at low cost. Further, when the composition C is molded, the composition C may be used at 100%, but one or more virgin materials such as resins and plasticizers may be added and used according to the application.

For molding of the composition C obtained by the present invention, a molding apparatus for a thermoplastic resin such as a normal calender molding machine, extrusion molding machine, injection molding machine, press molding machine, blow molding machine can be used. Can be used for building materials (floor materials, wall covering materials, waterproof materials, etc.), civil engineering materials, interior materials such as automobiles and railway vehicles, daily necessities, toys, miscellaneous goods and the like.

  Next, the present invention will be described in more detail with specific examples, but the present invention is not limited to these examples.

< Reference Example 1>
As the waste material A, foam type vinyl chloride resin (hereinafter referred to as PVC) wall covering waste material is used and pulverized with a pulverizer having a screen mesh diameter of 5 mm. After adding 10% by weight and heat-treating with 2 rolls (set temperature 150 ° C.) for 10 minutes, the sheet was taken out with a thickness of 5 mm and cut (granulated) into a 5 mm square with a sheet pelletizer.
Next, the obtained granulated product (Composition C) was formed into a sheet of 0.2 mm with a calendar molding machine at 175 ° C. The evaluation results are shown in Table 1.

<Evaluation method and evaluation criteria>
The formability and sheet surface state are evaluated, and the evaluation method and evaluation criteria are as follows.

[Formability]
In the case of calendar molding, judgment is made around the bank.
A: In the calendar, the bank circumference is good, and in the extrusion, there is no abnormality in the resin flow and the moldability is good.
○: An abnormality is recognized around the bank in the calendar and in the resin flow in the extrusion, but the molding can be performed.
X: It is difficult to form into a sheet.
[Sheet surface condition]
A: There is no rough skin or bubbles.
○: Rough skin and bubbles are observed but not noticeable.
X: Skin roughness is conspicuous.

< Reference Example 2>
As the waste material A, non-foamed PVC-based wall covering waste material was pulverized with a pulverizer having a screen mesh diameter of 10 mm, and the obtained pulverized material B was converted into a vent type 40 mm Φ single screw extruder (set temperature: 130 ° C., It was extruded (heat treated) to 3 mmΦ at a screw rotation speed of 60 RPM, and after cooling, it was cut (granulated) to a length of 5 mm by a strand cutting pelletizer.
Next, the obtained granulated product (composition C) was formed into a sheet of 0.8 mm at 180 ° C. with an extruder. The evaluation results are shown in Table 1.

< Reference Example 3>
As the waste material A, foam type PVC-based wall covering waste material is used and pulverized with a pulverizer having a screen mesh diameter of 5 mm. The obtained pulverized material B has 5% by weight of DOP as a plasticizer and is used as a stabilizer. Add 1% by weight of composite metal soap of barium oxide and zinc stearate, extrude to 3mmΦ (heat treatment) with bent type 40mmΦ single screw extruder (setting temperature 140 ℃, screw rotation speed 60RPM), cool and strand cut It was cut (granulated) to a length of 5 mm with a pelletizer.
Next, the obtained granulated product (Composition C) was formed into a sheet of 0.5 mm with a calendar at 180 ° C. The evaluation results are shown in Table 1.

<Example 4>
As the waste material A, foam type PVC-based wall covering waste material is used and pulverized with a pulverizer having a screen mesh diameter of 15 mm. To the obtained pulverized material B, 1% by weight of stearic acid as a lubricant is added, and 100 L It heat-processed for 10 minutes with high speed stirring with the Henschel mixer (setting temperature 150 degreeC, rotation speed 1200RPM), discharged | emitted to the cooler mixer, and granulated to the particle size of 1-20 mm.
Next, the obtained granulated product (Composition C) was formed into a sheet of 1.0 mm at 170 ° C. with an extruder. The evaluation results are shown in Table 1.

< Reference Example 5>
Non-foamed type olefin-based wall covering waste material is used as waste material A, and it is pulverized by a pulverizer having a screen mesh diameter of 10 mm. The resulting pulverized material B is bent type 40 mmΦ single screw extruder (set temperature: 150 ° C., screw It was extruded (heat treated) to 3 mmΦ at a rotation speed of 50 RPM, and after cooling, it was cut (granulated) to a length of 5 mm with a strand cutting pelletizer.
Next, the obtained granulated product (Composition C) was formed into a sheet of 0.3 mm with a calendar at 165 ° C. The evaluation results are shown in Table 1.

<Example 6>
As the waste material A, foam type olefin-based wall covering waste material is used and pulverized with a pulverizer having a screen mesh diameter of 5 mm. The resulting pulverized material B contains 1% by weight of zinc stearate as a lubricant and an antioxidant. 1% by weight of 2,2′-methylene-bis- (4-methyl-6-tert-butylphenol) was added and heat-treated while stirring at a high speed for 10 minutes with a 100 L Henschel mixer (setting temperature 140 ° C., rotation speed 1200 RPM). And it discharged to the cooler mixer and granulated to the particle size of 1-20 mm.
Next, the obtained granulated product (composition C) was formed into a sheet of 0.4 mm at 175 ° C. with an extruder. The evaluation results are shown in Table 1.

<Comparative Example 1>
As the waste material A, a foam type PVC-based wall covering waste material was used and pulverized with a pulverizer having a screen mesh diameter of 10 mm to obtain a pulverized material B.
Next, the pulverized material B was formed into a sheet of 0.8 mm with an extruder at 175 ° C. without performing heat treatment and granulation. The evaluation results are shown in Table 2.

<Comparative example 2>
Non-foamed PVC wall covering waste material is used as waste material A, and it is pulverized by a pulverizer having a screen mesh diameter of 10 mm. The resulting pulverized material B is bent type 40 mmφ single screw extruder (set temperature 120 ° C., screw It was extruded (heat treated) to 3 mmφ at a rotation speed of 60 RPM, and after cooling, it was cut (granulated) to a length of 5 mm with a strand cutting pelletizer.
Next, the obtained granulated product (Composition C) was formed into a sheet of 0.5 mm with an extruder at 170 ° C. The evaluation results are shown in Table 2.

<Comparative Example 3>
As the waste material A, foam type PVC-based wall covering waste material is used and pulverized with a pulverizer having a screen mesh diameter of 5 mm. The resulting pulverized material B has 10% by weight of plasticizer DOP as a stabilizer. Add 1% by weight of composite metal soap of barium acid and zinc stearate, heat-treat with high speed stirring for 10 minutes with 100L Henschel mixer (setting temperature 110 ° C, rotation speed 1200 RPM), discharge to cooler mixer Granulated to 20 mm.
Next, the obtained granulated product (Composition C) was formed into a sheet of 0.5 mm with a calendar at 180 ° C. The evaluation results are shown in Table 2.

スクリーン＊１：粉砕機スクリーンメッシュの口径（ｍｍ）
装置＊２（１）：２本ロール
（２）：ベントタイプの単軸押出機
（３）：内容量１００Ｌのヘンシェルミキサー
造粒＊３（イ）：シート用ペレタイザー
（ロ）：ストランドカット用ペレタイザー
（ハ）：内容量２００Ｌのクーリングミキサー

Screen * 1: Diameter of crusher screen mesh (mm)
Equipment * 2 (1): Two rolls (2): Vent type single-screw extruder (3): Henschel mixer granulation with an internal volume of 100 L * 3 (A): Sheet pelletizer (B): Strand cut pelletizer (C): 200L cooling mixer

スクリーン＊１、装置＊２、造粒＊３は表1と同じ

Screen * 1, equipment * 2, granulation * 3 are the same as in Table 1.

In Examples and Comparative Examples, it can be seen that, regardless of non-foaming and foaming, heat treatment is not performed, and heat treatment at 110 ° C. and 120 ° C. below 130 ° C. indicates that the surface state of the formed sheet is poor, and the temperature is 130 ° C. or higher. It can be seen that the heat treatment and granulation improve the moldability of the composition C and the surface state of the molded sheet. Moreover, it turns out that a moldability improves by adding a modifier during heat processing.

Composition C according to the production method of the present invention has good processability and surface condition, and is improved in handling property by granulation, and can prevent re-absorption by fibers of the backing paper, so that building materials (floor materials, wall covering materials) , Waterproof materials, etc.), civil engineering materials, interior materials such as automobiles and railway vehicles, daily necessities, toys, miscellaneous goods, etc., can be widely used as recycled materials.

Claims (3)

When recycling the waste material of thermoplastic resin wall covering (hereinafter referred to as waste material A), the waste material A is pulverized and then heat-treated by high-speed stirring at a temperature of 130 ° C. or higher to remove volatile components and cooling. A method for producing a recycled thermoplastic resin composition, comprising granulating with a mixer . The method for producing a recycled thermoplastic resin composition according to claim 1, wherein the waste material A is a foamed product. The method for producing a recycled thermoplastic resin composition according to claim 1, wherein a modifier is added during the heat treatment.