JPS58136424A - Ram extrusion-molding method for resin containing lubricant - Google Patents

Abstract

PURPOSE:To enable to perform an extrusion molding using resin containing a lubricant and to improve a yielding of a material, by a method wherein a pressurizing device is mounted to a heating cylinder, and a back pressure is applied to a molded work while a molded work being extruded is being pressurized in a manner to hold it between the nip formed by a pressurizing device. CONSTITUTION:If a powder material, being a resin containing a lubricant, is charged into a heated cylinder 4 through a material feed port 2, a ram 1 is moved to cure the powder material into a cake state for extrusion, and the aboves are continuously repeated to obtain an extrusion-molded product 5. In which case, a back pressure is applied to the extrusion-molded product 5. It is needed to appropriately select the extrusion pressure and the extruding speed of the ram matching a type, size, and a shape of a material. Waxes, oils, molybdenum disulfide are used as a lubricant, and not less than 1pt.wt., based on 100pts.wt. resin such as polyamide, ABS, polycarbonate, of the lubricant is contained.

Description

Detailed Description of the Invention When a molded product is continuously molded using a lubricant-containing resin powder using the present shouting and ram extrusion method, back pressure is applied to the extruded product to uniformly melt and integrate the extruded product. The present invention relates to a ram extrusion molding method for a lubricant-containing resin to form a molded article.

Conventionally, lubricant-containing cast nylon (for example, Japanese Patent Publication No. 52-39
Lubricant-containing resins such as (see Publication No. 8'78) have excellent self-lubricating properties, low friction coefficients, and good wear resistance, making them extremely useful as oil-free sliding parts such as bearings, gears, rollers, guides, and rails. . However, these sliding parts are generally manufactured by cutting out and machining raw materials such as round bars, pipes, and plates manufactured using the monomer casting method. Currently, there is no suitable recycling method for powder, etc., so it is no more than scrap.

By the way, resins that do not contain a lubricant can generally be extruded using a screw-type extruder, but such resins containing a lubricant cannot be extruded on the screw surface because of the lubricant in a screw-type extruder. , extrusion is virtually impossible. Similarly, molding using commonly used injection molding machines is also impossible.

Furthermore, even when using the ram extrusion method used for extrusion of ultra-high molecular weight polyethylene or fluororesin, it is necessary to apply sufficient pressure because the frictional resistance of the resin with the inner surface of the cylinder is reduced due to the influence of the lubricant. It is not possible to uniformly melt and integrate the inside of the product, making it impossible to obtain a molded product with excellent properties.

In some cases, there is a method of attaching a reverse taper (9-fold type) mouthpiece to the cylinder outlet of the ram extruder during ram extrusion (
JP-A-55-86731) and a method of using a lubricant-containing resin in a part of the reverse taper (JP-A-56-28839) have been proposed, but according to this method, the shape of the extruded product is .

If the dimensions or raw material composition change, the squeezing nozzle at the tip of the cylinder must be replaced each time and adjusted to apply an appropriate back pressure, which is complicated and costly. Furthermore, although crystalline resins whose viscosity rapidly decreases near their melting point can be extruded into the desired shape at temperatures 3 to 10 degrees Celsius below their melting point, amorphous resins whose viscosity does not rapidly decrease require a drawing die. When attached, the extrusion pressure increases rapidly and extrusion molding becomes extremely difficult.
This paper proposes an improved extrusion method for lubricant-containing resins that could not be extruded using conventional screw-type extruders.

That is, the feature of the present invention is that during ram extrusion molding of the resin, the extruded product is formed by sandwiching the extruded product between several pairs of rolls, caterpillars, etc. at the cylinder exit of the extruder. Extrusion molded products, such as round bars, are uniformly melted and integrated by applying back pressure.

The purpose is to continuously manufacture pipes, plates, etc.

Hereinafter, specific embodiments of the preform molding method of the present invention will be further described in detail.

1 and 2 show cross-sectional views of the ram extruder and pressurizer used in the method of the invention.

The ram extruder used here is of a plunger type, which is generally used for ram extrusion molding of ultra-high molecular weight polyethylene, fluororesin, etc. In the figure, (1) is the ram of the ram extruder, and the cylindrical cylinder (4)
The cylinder (4) is inserted at one end into the cylinder (4), and its axial sliding pushes out the raw material introduced into the cylinder (4).

Therefore, one end of the cylinder (4) has a raw material supply port +21.
A heater (3) is provided on the circumferential surface of the cylinder to heat the cylinder. and the cylinder (
At the outlet of 4), there is a pressure machine (8) to apply back pressure to the molded product.
) is arranged, and in FIG. 1, several pairs of rolls (6) are arranged in parallel as an example of such a pressurizer (8). −
In FIG. 2, two upper and lower caterpillar belts (71, <1f) are hung around a plurality of rolls (6) arranged in parallel.

These several pairs of rolls (6), the rolls (6), and the caterpillar belt (7) have a structure that applies a predetermined pressure to the extrusion molded product and insert it into the extrusion molded product. Adjust the clamping pressure, number of rolls (or caterpillar
The belt length) and roll diameter can be freely selected.

As the material of the roll (6) or the caterpillar belt (71), it is generally possible to use materials for ordinary rolls and caterpillar belts, and it is particularly desirable to use elastic bodies of various resin elastomers and rubber compositions.

However, when performing molding extrusion using the extruder described above, when the powder raw material of the lubricant-containing resin is introduced into the heated cylinder (4) from the raw material supply port (2), the ram (
11 moves to solidify the powder raw material into a cake shape and extrude it, and this process is continuously repeated to form an extrusion molded product (5). In this case, back pressure is applied to the extrusion molded product (5).

That is, in the method disclosed in FIG. 1, the molded product (5) is sandwiched between several pairs of rolls (6) by applying a predetermined pressure in a direction perpendicular to the flow direction of the molded product (5). In Fig. 2, the back pressure is applied by the caterpillar belts (7) (71') attached to the rolls shown in Fig. 1. It is also possible to apply back pressure to the molded article (5) by applying a rotational load of .

In the above case, the extrusion pressure and extrusion speed (cycle time,
It is necessary to appropriately select or adjust the shot amount), cylinder heater temperature, and capacity.

The lubricant-containing resin referred to in the present invention refers to lubricants such as waxes such as paraffin wax, microcrystalline wax, and montan wax, oils, molybdenum disulfide, graphite, and resins such as aliphatic polyamide, polyacetal, polyester, etc. Ethersulfono. Crystalline resins whose viscosity decreases rapidly near the melting point, such as polybutylene terephthalate, polyethylene terephthalate, and polystyrene, or polyamides, polyamideimides,
It is contained in 1 part by weight or more per 100 parts by weight of amorphous resin such as aromatic polyamide, ABS, polycarbonate, etc., and is in powder form with a particle size of 2 vm or less, preferably 1 m+ or less.

If the particle size exceeds 2w, the raw material will not aggregate into a cake during pre-pressing during ram extrusion, in other words, it will not be possible to back up to the raw material supply port and continuously supply the raw material. 1fc, among the above lubricant-containing resins, hygroscopic ones need to be dried at 100 to 120°C for 3 to 4 hours. Insufficient drying results in air bubbles in the extrudate.

Examples regarding the method of the present invention will be further shown below. However, it goes without saying that the present invention is not limited to these descriptions.

Example 1 Using a ram extruder with an inner diameter of 15 m and a length of 1300 m (with 3 heaters), the temperature was preliminarily heated to 110°C.
A lubricant-containing resin nylon (trade name: Mitsuboshi Cast Nylon O) consisting of poly ε-caprolactam xoo and 6 parts by weight of microcrystalline wax dried for 3 hours
The recycled powder product (particle size 1 m or less) of L) is applied to the cross section of the extruded round bar by sandwiching the formed round bar between three pairs of hard urethane rolls of the press machine shown in Figure 1 at the cylinder outlet. Extrusion molding was carried out under the conditions shown in Table 1 with a back pressure of 2 e lYa applied.

Margin below From the above results, the extruded cast nylon product containing lubricant used in Example 1 has a beautiful appearance that is uniformly melted and integrated to the inside with no significant difference in specific gravity and Izot impact test compared to non-recycled products. It was an excellent round bar. In addition, the molded product of Comparative Example 1, in which no back pressure was applied to the extruded round rod, was not fully compressed and melted, was not integrated, and was brittle and easily fell apart when handled by hand.

Example 2 Cylinder with inner diameter 50φ and length 2m (with 3 heaters)
19651 for the cross section of the round bar extruded by a pressurizer using a ram extruder with a A round bar was extruded in the same manner as in Example 1 by applying a back pressure of .

The ram extrusion conditions and results are shown in Table 29 and Figure 3.

Margin below Table 2 Ram extrusion conditions for round bar Table 3 Evaluation of extruded round bar He took advantage of the opportunity and followed the instructions of the queen.

Test piece: A 5-thick disk cut from an extruded round bar (approximately 49cm diameter) Compatible material: Cylindrical hard # (S*5o) Addition of lubricant during the test...・None friction speed V ”・50 m/+m (constant) surface pressure P,・
... Shifting by lOt every 10 minutes Dynamic friction coefficient μ ... The friction force at each pv value was measured and calculated using a load cell directly connected to a torque lever.

Limit PV value: Product of surface pressure P and friction speed V when surface pressure control becomes impossible. However, W: Wear of the test piece at the limit PV value 11 (mf) P: Surface pressure (shi) ■ =Friction speed (constant 50 rV/'') From the above results, the lubricant-containing cast nylon used in Example 2 and the extruded round bar were compared with the lubricant-containing cast nylon before recycling in Tables 3 and 3. As shown in the figure, there was no significant difference in friction and wear tests, and it was found that the material could be used satisfactorily as a material for sliding parts such as bearings, gears, and rollers.

In addition, the extruded rod of Comparative Example 2, in which no back pressure was applied, was not fully melted internally and was not integrated, and in the friction and wear test, the dynamic friction coefficient was much lower than that of Example 2 and the rod before regeneration. No difference is observed, but the limit pv value is 3000Y4
・25 to 3 compared with 1 idiom and Example 2 and the one before reproduction
It turned out that the decline was 3%.

In addition, comparative example 2 has a steady wear amount of 511X10-3mVY4
・w′ turtle・The power is about 3.1 times larger than that of Example 2,
It was easy to wear out.

As described above, the method of the present invention applies back pressure to the extrudate using a pressurizer during ram extrusion molding of a lubricant-containing resin, thereby uniformly melting and integrating the product, and continuously obtaining extrudates with excellent physical properties. This enables the extrusion molding of lubricant-containing resins that could not be remolded up until now, and the effective use of cut pieces and chips generated during manufacturing and machining of the resin materials improves the yield of raw materials. It has a remarkable effect,
It is also extremely significant industrially.

[Brief explanation of drawings]

Figures 1 and 2 are cross-sectional views showing the ram extrusion mode and each side of the pressurizer used in the method of the present invention, and Figure 3 is the surface pressure at constant friction speed (V = 50rr4/'') in a friction and wear test. It is a chart showing the relationship between P and the coefficient of dynamic friction μ. (1)...Ram, (3)...Heating heater. (4)...Cylinder, (5)...Extrusion molded product. 8)...pressure machine.

Claims (1)

[Claims]! In a method in which resin powder containing a lubricant is put into a heating cylinder and extruded using a ram, a pressure machine is installed at the outlet of the cylinder, and the molded product is clamped and pressurized by the pressure machine. A ram extrusion molding method for lubricant-containing resin characterized by applying back pressure. 2. The resin containing the lubricant is aliphatic polyamide. Claim 1: The resin contains 1 part by weight or more of a lubricant per 100 parts by weight of one or more resins selected from polyester, polyether sulfone, polybutylene terephthalate, polyethylene terephthalate, and polystyrene. A ram extrusion molding method for the lubricant base 1v resin described above. 3. The resin containing the lubricant is polyamide, polyamideimide, aromatic polyamide, ABi9. The method for ram extrusion molding of a lubricant-containing resin according to claim 1, wherein the resin contains 1 part by weight or more of a lubricant in 100 parts by weight of one or more amorphous resins selected from polycarbonates. 'A Lubricants are waxes, oils, and molyphane disulfide. A method for ram extrusion molding a resin containing a lubricant according to claim 1, 2 or 3, wherein the lubricant-containing resin is one or more selected from graphite. A method for ram extrusion molding of a lubricant-containing resin as described in Section 3.