JPH08230052A - Plastic molded product - Google Patents

Abstract

PURPOSE: To enable outdoor use by specifying the coefficient of linear expansion and Charpy impact strength of a molded product molded from waste plastic to which at least mica is added. CONSTITUTION: The coefficient of linear expansion of a molded product molded from waste plastic to which at least mica is added is set to 10×10<-5> cm/cm. deg.C or less and the Charpy impact strength thereof is set to 4kgf.cm/cm<2> or more. This molded product has a wood grain outer surface and contains 60wt.% or more of polyolefin and the addition amt. of mica per 100 pts.wt. of waste plastic is 5-100 pts.wt., pref., 20-60 pts.wt. When this plastic molded product 6 is used as a pillar, a pile or a fence material, plastic, mica and, if necessary, additives such as pigment are mixed to be subjected to co-extrusion using a reinforcing metal pipe as a core material or to be injected into a mold while the metal pipe 7 is inserted.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a plastic molded article. More specifically, the present invention is a molded product formed by using waste plastic, has a small linear expansion coefficient, a large impact strength, and can be suitably used for outdoor applications such as civil engineering materials, playground equipment, and park materials. Plastic molded articles that can be made.

[0002]

2. Description of the Related Art In recent years, waste treatment has become a major social problem, and its reuse is strongly demanded. The amount of waste plastics is also increasing year by year, and their reuse will solve the processing problems and save limited resources. Since plastics generally have a large coefficient of linear expansion, in the case of molded products that are used outdoors, they are heated by direct sunlight to expand and bend, and at low temperatures they shrink and cause gaps and damages in the connected parts of the molded products. There is a problem such as. Further, in the case of waste plastic, since it is a mixture of various resin molded products, there is a problem that molding processing and quality control are difficult, which makes reuse difficult. The prior art of adding an inorganic filler such as mica to a resin under specific conditions is disclosed in Japanese Patent Laid-Open No. 18503/1993.
As disclosed in Japanese Patent Publication No. 8 and Japanese Patent Publication No. 5-42975, all of them use a new resin, and are also used for audio equipment, indoor equipment, etc., and are required for molded products used outdoors. It did not require resistance to expansion and contraction due to temperature changes. Generally, wood powder, glass fiber, calcium carbonate, etc. are added as a method for reducing the linear expansion coefficient of plastics. However, since wood powder usually contains 10% by weight or more of water, drying or surface treatment There is a problem that treatment is necessary, glass fibers are heavily worn by equipment during processing, and granular materials such as calcium carbonate are significantly embrittled.

[0003]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a plastic molded product made of waste plastic as a raw material, which has a small linear expansion coefficient, is excellent in impact resistance and can be used outdoors. It is a thing.

[0004]

Means for Solving the Problems As a result of intensive studies to solve the above problems, the inventors of the present invention have formed a plastic having a low linear expansion coefficient and a high impact strength by molding it by adding mica to the waste plastic. It was found that the product can be used outdoors, and the present invention has been completed based on this finding. That is, the present invention is (1) a molded product formed by adding at least mica to waste plastic, having a linear expansion coefficient of 10 × 10 ⁻⁵ cm / cm · ° C. or less and a Charpy impact strength of 4 kgf · cm. / Cm ² or more, a plastic molded article characterized by the above. further,
As a preferred embodiment of the present invention, (2) the plastic molded article according to item (1), wherein the plastic molded article is an outdoor molded article, and (3) the outer surface has a skin-like texture (1) to (2). (4) The waste plastic contains 60% by weight or more of polyolefin (1) to
(3) The plastic molded article, (5) The plastic molded article according to any one of (1) to (4), wherein the added amount of mica is 100 to 100 parts by weight of the waste plastic.
(6) The plastic molded product according to the items (1) to (5), wherein the amount of mica added is 100 to 100 parts by weight of the waste plastic, and the linear expansion coefficient is 5.0 ×. 10
^-5 cm / cm ・ ° C or less, Charpy impact strength is 5 kgf ・ c
The plastic molded articles according to the items (1) to (6) having a m / cm ² or more can be mentioned.

In the present invention, waste plastic is used as a raw material for molded articles. The waste plastic to be used is not particularly limited as long as it is a thermoplastic resin, for example, polyethylene, polypropylene, polybutene-1, polyolefin such as poly-4-methylpentene-1, polyvinyl chloride,
Chlorine-containing resins such as polyvinylidene chloride, polyesters such as polyethylene terephthalate and polybutylene terephthalate, polyamides such as nylon 6, nylon 66, polystyrene, styrene resins such as ABS, acrylic resins such as polymethylmethacrylate, and other polyvinyl alcohols. Polyvinyl acetate etc. can be mentioned. Among these waste plastics, in order to obtain a molded article having high impact strength, those containing 60% by weight or more of polyolefin-based plastics are preferable, and those containing 70% by weight or more are more preferable. Many of the waste plastics sorted by type of plastic usually contain 10% by weight or more of different types of plastics, but the plastic molded product of the present invention thus contains different types of plastics. Manufactured from waste plastic.
The source of the waste plastic used in the present invention is not particularly limited, and for example, used containers, cases, tanks, bottles, sheets, and the like, which can be used as molded articles used in the market, are generated in a molding factory. Scrap plastic can be used, or substandard plastic raw materials can be used.

In the present invention, mica or the like is added to waste plastics and molded to obtain a molded product. The mica to be used is not particularly limited, and it includes muscovite, biotite, lepidolit.
e), soda mica (paragonite) and the like can be used. The amount of mica added to the waste plastic is preferably 5 to 100 parts by weight, more preferably 10 to 60 parts by weight, and even more preferably 20 to 60 parts by weight, per 100 parts by weight of the waste plastic. If the added amount of mica is less than 5 parts by weight per 100 parts by weight of waste plastic, the linear expansion coefficient of the molded product may not be sufficiently small. If the added amount of mica exceeds 100 parts by weight per 100 parts by weight of waste plastic. The workability may deteriorate. The plastic molded article of the present invention includes, in addition to mica, a filler, a reinforcing material, a coloring pigment,
An ultraviolet absorber, an antioxidant, an antistatic agent, a flame retardant, etc. can be added. Examples of the filler include talc, calcium carbonate, glass beads, clay, kaolin, wollastonite, diatomaceous earth and the like. Examples of the reinforcing material include glass fiber and carbon fiber. As the coloring pigment, for example,
Examples thereof include titanium oxide, zinc oxide, yellow iron oxide, titanium yellow, red iron oxide, ultramarine blue, and carbon black. Examples of the ultraviolet absorber include salicylic acid pt
-Butylphenyl, 2-hydroxy-4-methoxybenzophenone, 2- (2'-hydroxy-5'-methylphenyl) benzotriazole and the like can be mentioned. As the antioxidant, for example, 2,6-di-t-butyl-
Examples thereof include p-cresol, dilaurylthiodipropionate, triphenyl phosphite and the like. Examples of the antistatic agent include polyoxyethylene alkylamine, alkylbenzene sulfonate, quaternary ammonium chloride and the like. As a flame retardant,
For example, tricresyl phosphate, tris phosphate (2,3-
Dibromopropyl), chlorinated paraffin, antimony trioxide and the like. The blending amount of these additives can be appropriately selected depending on the intended use of the plastic molded product.

The plastic molded article of the present invention has a linear expansion coefficient of 10 × 10 ⁻⁵ cm / cm · ° C. or less. Coefficient of linear expansion is 10
If it exceeds × 10 ^-5 cm / cm · ° C, the dimensional change due to the temperature difference due to the temperature rise due to direct sunlight and the temperature decrease at night becomes large, and the molded product cannot be used outdoors. The linear expansion coefficient can be measured according to JIS K 7197. The plastic molded article of the present invention has a Charpy impact strength of 4 kgf · cm / cm ² or more. If the Charpy impact strength is less than 4 kgf · cm / cm ² , there is a risk of damage when drilling holes for fixing bolts or unloading, and during use, heavy or hard objects may hit and be damaged. The Charpy impact strength in the present invention is JISK
It is a value obtained by performing the flatwise impact test specified in 7111 on the No. 1 test piece subjected to A notch processing. The plastic molded product of the present invention may be provided internally with a metal reinforcing material such as a metal pipe or a square rod, if necessary. General plastics have a larger coefficient of linear expansion than ordinary metal, and when a metal reinforcement is provided inside, the contact surface between plastic and metal causes contraction failure due to temperature change,
Although the reinforcing effect sharply decreases, the plastic molded product of the present invention has a small linear expansion coefficient, so that it can maintain good contact with the metal reinforcing material for a long period of time and maintain the reinforcing effect. The plastic molded article of the present invention has a plate shape for outdoor applications such as bridge girders, bridge piers, pillar materials, bench materials, playground equipment such as parks, earth retaining materials, etc.
It has a tubular shape, a log shape, a square shape, or the like, and can be suitably used as a thick product, a heavy product, a long product, and the like. Further, the molded product according to the present invention exhibits a grainy appearance due to the unevenness of the outer surface, the color condition, etc., and is more suitable for outdoor use. Further, in the case of conventional wood products and plastic molded products, considerable frictional heat is generated between the cutting opening and the cutting tool (saw etc.) at the time of cutting in molding processing, and it is difficult to cut without a lubricant, whereas the molded product of the present invention Can be easily cut without this type of lubricant and has excellent workability.

When the plastic molded product of the present invention is used as a bench material, waste plastic, mica, and other additives such as pigments are charged into the hopper of the extruder, or mica is separately charged in a fixed amount and extruded. Perform molding. Cylinder temperature and die temperature of the extruder are 180 ~ 250 ℃
It is desirable to set to. The plastic extruded from the die is poured into a mold and cooled and molded. The plastic molded product is then attached to the bench-shaped metal reinforcement made from pipes, square bars, etc. with screws or bolts,
Assemble it into a bench. Plastic moldings (for example, bench materials) and metals (reinforcing materials) repeat expansion and contraction due to yearly temperature differences and day and night temperature differences, but if the difference in the linear expansion coefficient of both exceeds the allowable range, it will become bench material. A large stretching or compressing force is applied, the bench material is damaged, the fixing portion is loosened, and the bench becomes useless. FIG. 1 is an explanatory view of a bench material made of a plastic molded product. FIG.
(A) shows a state in which the bench material is attached to the metal reinforcing material and assembled on the bench. In this figure, the bench material 1 is
It is attached to the metal reinforcing member 3 with a fixing bolt 2. FIG.1 (b) shows the state of the bench when a direct sunlight starts to hit. Since direct sunlight directly hits the bench material surface 4 and does not directly hit the bench material back surface 5, there is a temperature difference between the bench material front surface and back surface, and if the bench material has a large linear expansion coefficient, As a result of the difference in expansion and the elongation of the surface, the bench material is deformed so as to project upward.
FIG. 1C shows the state of the bench when the sunshine duration has elapsed. The linear expansion coefficient of the bench material is 10 × 10 ^-5 cm / cm ・ ℃
If the temperature exceeds the above value, the temperature of the entire member rises with the elapse of the sunshine time, the member expands and the convex deformation becomes remarkable, and the fixing bolts at both ends extend outward due to the force F ₁ and upward due to bending. F ₂ is applied, the bolt holes of the member is deformed. FIG.1 (d) shows the state of the bench at night. When the temperature decreases at night, the bench material contracts, and the inward force F ₃ due to the contraction is applied to the fixing bolt, and the bolt hole is deformed. By repeating such deformation every day, the bolt fixing part is loosened and the bench is damaged without time. Since the plastic molded product of the present invention has a coefficient of linear expansion of 10 × 10 ⁻⁵ cm / cm · ° C. or less, when it is used as a bench material, such deformation occurs and excessive force is applied to the bolt portion. It can be used stably for a long period of time. If the plastic molded product used as a bench material has a Charpy impact strength of less than 4 kgf · cm / cm ² , there is a possibility that cutting or damage may occur during processing of the fixing bolt hole or during unloading. Also, when used as a bench, heavy objects may fall on the bench,
If a playground equipment or the like collides, it may be damaged. The plastic molded product of the present invention has a Charpy impact strength of 4 kgf · cm.
/ Cm ² or more, there is very little risk of damage during processing, transportation and use.

When the plastic molded article of the present invention is used as a pillar, a pile or a fence material, as in the case of using it as a bench material, plastic, mica, and other additives such as pigments are mixed as necessary to form a reinforcing metal. Coextrusion using a pipe as a core material is performed, or a metal pipe is inserted and injected into a mold. The pillars, piles and fences thus obtained are reinforced by metal pipes so that the pillars or piles are erected at regular intervals and lateral fences are attached so that they will not break even if an object collides. FIG. 2 is an explanatory diagram of columns, piles, and fences made of plastic molded products. In this figure, a metal pipe 7 is inserted into the plastic 6. Linear expansion coefficient of plastic molding is 10 × 10
^If it exceeds ^-5 cm / cm ・ ° C, the shrinkage of the plastic molded product due to the temperature decrease at night or in winter is large, and the large shrinkage force F ₄
Occurs. Due to the reinforcing metal pipe, the plastic molded product cannot shrink, while the shrinkage force continues, so that a cut 8 occurs in the weak part of the plastic molded product over time. When the base of the pile is fixed with concrete, the coefficient of linear expansion is 10 × 10 ^-5 cm / cm ・ ° C.
When it exceeds, the concrete tends to be damaged by the expansion of the plastic molded product due to the temperature rise. Since the plastic molded article of the present invention has a coefficient of linear expansion of 10 × 10 ⁻⁵ cm / cm · ° C. or less, there is almost no possibility of causing such breakage or breakage. If the Charpy impact strength of the plastic moldings used as pillars, piles, and fences is less than 4 kgf · cm / cm ² , it may be damaged during unloading or may be damaged when hit by a hard object. Since the plastic molded article of the present invention has a Charpy impact strength of 4 kgf · cm / cm ² or more, there is almost no possibility of causing such damage or breakage.

[0010]

The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. In the examples and comparative examples, the coefficient of linear expansion and the Charpy impact strength were measured as follows. (1) Linear expansion coefficient A test piece of 5 × 5 × 10 mm was cut out from the molded product and JIS
It was measured according to K 7197. (2) Charpy impact strength A test piece with a thickness of 4 mm, a width of 10 mm and a length of 80 mm was cut out from the molded product, and the tip radius was 0.25 mm in the thickness direction at the center of the long side.
A notch with a depth of 0.8 mm is added, and JIS K7111
Was measured according to. Example 1 Waste plastic B10 having a polyolefin content of 70% by weight
A mixture of 0 parts by weight, 15 parts by weight of mica and 1 part by weight of pigment is melted, kneaded and extruded by using an extruder, poured into a mold and cooled and molded, and the thickness is 50 mm, the width is 200 mm and the length is 1200.
The bench material of mm was obtained. When the linear expansion coefficient and the Charpy impact strength of the bench material were measured, the linear expansion coefficient was 8.4 × 1.
0 ^-5 cm / cm ・ ℃, Charpy impact strength is 5.2 kgf ・
It was cm / cm ² . FIG. 3 is a front view (a), a plan view (b) and a side view (c) of the bench model used in the present embodiment. 50 x 5 in 150 x 75 mm iron channel 9
On the leg material produced by welding the iron angle 10 of 0 mm, bolt holes centered at 4 points of 100 mm from the end of the bench material 1 in the length direction and 50 mm from the end in the width direction were formed, and a 12 mm bolt 11 was formed. Using the nut 12, a nut was tightened with a torque wrench at a tightening torque of 100 kgf · cm, and the bench material was fixed to the leg material to obtain a bench model. Assemble 2
Two bench models were prepared at 3 ° C. One bench model was heated at 50 ° C for 4 hours, cooled at 20 ° C for 4 hours, repeated 5 times, left at 23 ° C for 24 hours, and the retightening torque of the nut was measured.
cm and the nut did not loosen at all. Another bench model was placed horizontally on the floor of the room at 23 ° C, and a weight of 14 cm in diameter and 10 kgf was dropped from the height of 1 m in the center of the bench material, but the bench material was not damaged. Did not happen. Examples 2 to 3 Using the same waste plastic B, mica and pigment as in Example 1, the same operation as in Example 1 was repeated according to the formulation in Table 1. The results obtained are shown in Table 1. Examples 4 to 8 Instead of waste plastic B, the polyolefin content is 8
The same operation as in Example 1 was repeated with 0% by weight of waste plastic A and the formulation shown in Table 1. The results obtained are shown in Table 1. Comparative Example 1 The same operation as in Example 1 was repeated using a mixture of 100 parts by weight of waste plastic A, 3 parts by weight of mica and 1 part by weight of pigment. The results obtained are shown in Table 1. Comparative Example 2 The same operation as in Comparative Example 1 was repeated except that mica was not added. The results obtained are shown in Table 1. Comparative Examples 3 to 4 Instead of the waste plastic A, a polyolefin content of 50
The exact same operation as in Comparative Examples 1 and 2 was repeated using the weight% of waste plastic C. The results obtained are shown in Table 1.

[0011]

[Table 1]

The plastic molded articles of Examples 1 to 8 of the present invention have a small linear expansion coefficient and a large Charpy impact strength.
From the results of Examples 1 to 3 and Examples 4 to 8, it can be seen that when the same waste plastic is used, the linear expansion coefficient becomes smaller and the Charpy impact strength becomes larger as the blending amount of mica increases. In addition, the fifth embodiment is more than the first embodiment.
Example 6 is smaller than Example 2 and Example 7 is smaller than Example 3 in spite of the smaller amount of mica compounded, but the linear expansion coefficient is small and the Charpy impact strength is large. It can be seen that a large polyolefin content is effective in reducing the linear expansion coefficient and improving the Charpy impact strength. A large re-tightening torque indicates that the nut is not loosened, but the re-tightening torques in Examples 1 to 3 and Examples 5 to 8 are all equal to or higher than the initial tightening torque, and the heating / cooling cycle is the same. The nut is not loosened at all. Further, it can be seen that the smaller the linear expansion coefficient of the plastic molded product, the larger the re-tightening torque, and the smaller linear expansion coefficient is effective in preventing the nut from loosening. Further, it was confirmed that all bench materials using the plastic molded product of the present invention were not damaged by the drop weight test, and were excellent in practical strength. The plastic molded product of Comparative Example 1 containing a small amount of mica has a Charpy impact strength of 4.8 kgf · cm / cm ² , but a large linear expansion coefficient of 12.2 × 10 ⁻⁵ cm / cm · ° C. The bench material using this plastic molded product is not damaged by the falling weight test, but the retightening torque after heating and cooling is 48 kg.
It is less than half of the initial tightening torque of f · cm, and it can be seen that the nut is extremely loose. The plastic molded product of Comparative Example 2 in which mica was removed from the formulation of Comparative Example 1 had a larger linear expansion coefficient and a smaller Charpy impact strength than Comparative Example 1, and a bench material using the plastic molded product of Comparative Example 2 was obtained. Was damaged in the falling weight test, and the re-tightening torque of the nut was about one third of the initial tightening torque. The results of Comparative Example 3 and Comparative Example 4 using the waste plastic having a smaller polyolefin content than those of Comparative Example 1 and Comparative Example 2 were even worse, and the reduction of the polyolefin content in the waste plastic also caused the Charpy impact to the linear expansion coefficient. It was confirmed by these examples that the strength was also adversely affected.

[0013]

EFFECTS OF THE INVENTION A plastic molded product using the waste plastic of the present invention has a small linear expansion coefficient, a large Charpy impact strength, an outer surface of a skin texture, and is excellent in workability. Can be suitably used for outdoor benches, pillars, piles, fences, etc., which have a large temperature difference due to cooling at night and are often subjected to external impact.

[Brief description of drawings]

FIG. 1 is an explanatory view of a bench material made of a plastic molded product.

[Fig. 2] Fig. 2 is a pillar, a pile, and a plastic molded product.
It is explanatory drawing of a fence material.

FIG. 3 is a front view, a plan view and a side view of a bench model used in an example.

[Explanation of symbols]

 1 Bench Material 2 Fixing Bolt 3 Metal Reinforcement Material 4 Bench Material Front Surface 5 Bench Material Back Surface 6 Plastic 7 Metal Pipe 8 Cutting Damage 9 Iron Channel 10 Iron Angle 11 Bolt 12 Nut

Claims (1)

[Claims] 1. A molded product formed by adding at least mica to waste plastic and having a linear expansion coefficient of 10 × 10 ⁻⁵ cm /
cm ・ ℃ or less, Charpy impact strength is 4kgf ・ cm / cm ²
A plastic molded product characterized by the above.