JPH11138616A - Mouthpiece for manufacturing molding resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent gum-like matter from developing and piling up at a surface layer part in the polymer passing part and near the outlet of a discharge orifice of a mouthpiece by a method wherein the surface layer part in the polymer passing part and near the outlet of the discharge orifice of the mouthpiece for manufacturing molding resin composition are covered with vanadium carbide. SOLUTION: A plurality of discharge orifices pass through a mouthpiece. A melted resin composition enters the mouthpiece from the direction indicated with the arrow A and is discharged through the polymer passing part 3 from the outlet 4 of a discharge orifice in the fashion of strands. In this case, the surface layer part of the polymer passing part 3 and near the outlet 4 of the discharge orifice of the mouthpiece is covered with vanadium carbide. A vanadium carbide covering is executed by a TD process or by forming a carbide layer on the surface of a material by immersingly keeping the material such as a steel, a cemented carbide or the like in a molten salt held at high temperature. At the covering, the polishing work with a reamer polishing is preferable so as to realize the surface roughness by center-line mean roughness of 1.1 μm Ra.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used in a discharge section of an extruder in a process of producing a resin melted in a process of producing a resin-based material and a molding resin composition containing various fillers and additives. This is related to the base that is used.

[0002]

2. Description of the Related Art In general, in order to produce a molding resin composition, a resin and various fillers and additives are compounded and kneaded in an extruder, and the resin is melted from a die having a discharge hole of a predetermined size. The resin composition is extruded into a strand shape, cut, and pelletized. The die used for such a method is usually made of metal, but some of them are made of ceramics containing 40% by weight or more of zirconia as shown in, for example, JP-A-61-24973. . Further, in a die for producing a resin composition for molding, as shown in JP-A-5-220811, the surface roughness of the inner surface of the discharge hole and the vicinity of the outlet of the discharge hole is represented by a center line average roughness (Ra) by a replica method. Ra ≦ 5μ
m, and those in which the inner surface of the discharge hole and the vicinity of the outlet of the discharge hole are covered with a fluororesin as disclosed in JP-A-5-220812.

[0003]

When the resin composition for molding is continuously discharged from the die used for the discharge portion of the molding resin composition, a scum-like material adheres to the vicinity of the outlet of the die discharge hole. . The components of the cane-like material are sublimates of residual monomers and residual oligomers contained in the resin, condensates of volatile components of various additives, the resin composition itself, and the adhered cane-like material. Accumulates, and if left as it is, becomes discolored foreign matter due to oxidative deterioration or the like. If a part of the discolored foreign matter is mixed into the product, and it is made into a molded product by injection molding, the discolored cane-like material appears on the surface of the molded product and the appearance of the product And other problems such as impairing product quality, resulting in a significant decrease in commercial value. Many complaints due to the slime-like material also occurred, and various measures have been taken to deal with this, but it has not been sufficient, and there has been a long-awaited solution for manufacturers of molding resin compositions.

[0004] The above-mentioned ceramic mouthpiece has been devised for the purpose of preventing the occurrence of such a scum-like material. In the case of ceramics, although the amount of the scum-like material is reduced, the processing at the time of manufacture of the mouthpiece is required. There are drawbacks such as poor properties, weakness against impact, and high manufacturing cost.

[0005] Further, when a die for a molding resin composition disclosed in Japanese Patent Application Laid-Open Nos. 5-220811 and 5-220812 is used, it is possible to greatly reduce the amount of scum-like material deposited. When a molding resin composition containing various fillers, particularly glass fiber chopped strands, is discharged for a long time, the inner surface of the discharge hole and the surface in the vicinity of the discharge hole outlet are roughened. As a result, the effect of preventing the generation and accumulation of scum-like materials is reduced. In either case, the effect can be reproduced by re-polishing and re-coating, but the use cycle of the die is short, and the cost of polishing and coating increases.

[0006]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies on a die for a molding resin composition and a method for producing the molding resin composition for preventing the generation and accumulation of a scum-like material, and as a result, it was found that the die polymer passed through the die. Attention was paid to the coating process in the vicinity of the surface layer portion and the outlet of the discharge hole in the portion, and the present invention described below has been achieved as enabling these.

That is, the present invention provides a die for producing a molding resin composition having a polymer passing portion, wherein the surface layer portion of the polymer passing portion and the vicinity of the discharge hole outlet are covered with vanadium carbide. It consists of a resin composition manufacturing base.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be specifically described below.

In the present invention, the term "resin composition for molding" refers to a resin (single resin) used for molding such as injection molding or extrusion molding, a composition of resin and another resin (resin alloy), or a mixture of these resins. It is a general term including a composition in which reinforcing fibers, fillers, additives, and the like are added to a resin alloy. In addition, a thermoplastic resin is usually used as the resin of the present invention, and has a property of generating fluidity by heating, and is a resin that can be molded and processed using the same.For example, polyamide, polyester, polyphenylene oxide, polyacetal, polycarbonate , Polypropylene, polyethylene, polystyrene, polyphenylene ether, polybutylene terephthalate, polyphenylene sulfide, liquid crystal polymer, polyether sulfone, SBS, SEBS, acrylonitrile, styrene copolymer, acrylonitrile / styrene / butadiene copolymer, and the like. .

The term "die for molding resin composition" refers to a die used for a discharge portion of an extruder when the above-mentioned resin composition for molding is melted and discharged in the form of a strand. The area is generally 0.5 to 30.0 mm ² , preferably 4.0 to 15.0 mm ² .

A typical example of a die for a resin composition for molding used in the present invention is shown in FIG. 1 and FIG. FIG. 1 is a front view (discharge side) of the base, and FIG. 2 is a sectional view taken along the line XX ′ in FIG. 1 and schematically shows a base polymer passage portion.
A plurality of discharge holes 2 penetrate the base 1, and the molten resin composition enters in the direction of arrow A, and is discharged in a strand shape from the discharge hole outlet 4 through the polymer passing portion 3.

When coating the vicinity of the polymer passage portion 3 and the outlet hole outlet 4 of the base with vanadium carbide, the surface roughness is expressed as center line average roughness (Ra).
It is preferable to perform polishing by reaming so as to have a thickness of 1 μm. Here, the center line average roughness (Ra) is
It represents the value defined by JIS B 0601 and measured by the replica method. The replica method is to create a replica of an object to be measured using a rapidly curable resin, measure the surface roughness of the replica, and obtain the center line average roughness (Ra). The rapid-curing resin used here was a methyl methacryl-based room-temperature rapid-curing resin (trade name: Technobit 3).
040). The surface roughness is measured by a stylus method using a surface roughness meter (SURFCOM1014B) manufactured by Tokyo Seimitsu Co., Ltd.

In the present invention, the polymer passing portion 3 of the base is used.
It is necessary to cover the surface layer and the vicinity of the discharge hole outlet 4 with vanadium carbide. Vanadium carbide coating is a TD process (Toyota Diffusion Coating) developed at Toyota Central Research Laboratory, Inc.
PRO-CESS) may be used. The TD process is a method of forming a carbide layer on the surface of a material by immersing and holding a material such as steel or cemented carbide in a molten salt bath maintained at a high temperature. Can form an excellent vanadium carbide coating.

A specific coating method will be exemplified. First,
Degreasing and preheating (stepwise at 400 ° C./600° C. for 0.5 hr or more) is performed as pretreatment for the base as a base. Next, the preheated die is immersed and held in a molten salt bath kept at 1,000 ° C. for 12 hours in a furnace for TD process. At this time,
The vanadium in the salt bath and the carbon contained in the base material are combined to form a carbide layer on the surface of the base, and this carbide layer becomes a vanadium carbide coating layer, and the thickness of the coating layer is 4 μm.
m to 15 μm are generally preferred. Next, quenching of the die is performed using a heat treatment facility, and the hardness of the coating layer after the treatment is about Hv3,500 in Micro Vickers hardness,
Very high hardness. Finally, the coating process is completed through a step of washing and removing foreign substances attached to the surface of the die.

In the production process of the molding resin composition, particularly, a die used for producing a reinforced resin composition such as a glass fiber reinforced resin composition has a high abrasion rate, and thus has a large surface roughness and a large scum. Is easy to occur. On the other hand, it is considered that the cause of the adhesion and deposition of the scum in the vicinity of the outlet of the base is due to the adhesion of the scum to the metal,
A part of the slime-like material attached near the outlet of the discharge hole is in a molten state at a high temperature, and has a high affinity for metal and easily adheres. In the present invention, the surface layer portion of the base polymer passing portion and the vicinity of the outlet of the discharge hole are covered with vanadium carbide, and by utilizing its excellent characteristics, abrasion is suppressed, and peeling of the cane-like material from the metal surface is also achieved. And adhesion and deposition are prevented.

[0016]

The present invention will be specifically described below with reference to examples.

<Embodiment 1> The base is made of alloy tool steel S
Using KD-11, the number of discharge holes having the shape of the polymer passing portion shown in FIG. 2 was 60, and the surface roughness of the surface layer portion of the polymer passing portion and the vicinity of the outlet of the discharge hole were the center line average roughness (R) by the replica method.
Using a substrate of 1.1 μm in a), a vanadium carbide layer was coated to a thickness of 7 μm to 8 μm by the TD process described above. This die was set in a conventional twin screw extruder, and 70 parts by weight of 66 nylon having a relative viscosity of 2.60 and a length of 3 m
m, glass fiber chopped strand 3 with a diameter of 13 μm
0 parts by weight were melt-kneaded, and a strand having a sectional area of 7 mm ² was discharged from the discharge hole. When 500 tons of these resin compositions were manufactured in 500 hours, the amount of the scum was measured every 100 hours as the amount adhered during that time, and the center line average roughness (Ra) of the surface portion of the polymer passing portion after 500 hours was further measured. ) Was measured.

<Comparative Example 1> The base was made of alloy tool steel S
Using KD-11, the number of discharge holes having the shape of the polymer passing portion shown in FIG. 2 was 60, and the surface roughness of the surface layer portion of the polymer passing portion and the vicinity of the outlet of the discharge hole were the center line average roughness (R) by the replica method.
Use a material having a diameter of 1.1 μm in a) and do not perform any coating treatment. This die was set in a conventional twin-screw extruder, and 70 parts by weight of 66 nylon having a relative viscosity of 2.60 and 30 parts by weight of a glass fiber chopped strand having a length of 3 mm and a diameter of 13 μm were melted and kneaded, and a cross-sectional area of 7 mm from the discharge hole was obtained. ^Two strands were discharged. These resin compositions were prepared for 500 hours in 500 hours.
In the same manner as in Example 1, the amount of the slime-like material and the center line average roughness (Ra) of the surface layer portion of the polymer passing portion were measured.

In Example 1 and Comparative Example 1, the amount of the slime-like material and the center line average roughness (Ra) of the surface layer of the polymer passing portion were measured.
Are shown in Table 1.

As is clear from the results shown in Table 1, the amount of the slime-like material when the die for producing the resin composition for molding of the present invention is used is the amount of the slime-like material when the die which is not coated at all is used. 1/10 to 1/160, and
In the case of a base that has not been coated at all, the amount of the scum-like material sharply increases after about 300 hours of use time, whereas when the base for manufacturing a molding resin composition of the present invention is used, the base is not used. Even after 500 hours, there is almost no change in the amount of scum.

Further, the center line average roughness (Ra) of the polymer passing portion after using the base for 500 hours was measured. As a result, the base without any coating treatment had Ra = 7.9 μm. It can be seen that the die for producing a resin composition for molding of the present invention had Ra = 1.2 μm, and the surface was hardly roughened.

[0022]

[Table 1]

[0023]

According to the present invention, when the die for producing a resin composition for molding of the present invention is used, it is possible to drastically reduce the number of slimes generated, adhered and deposited during the production of the resin composition. It is possible to prevent a decrease in the commercial value of the product due to mixing. Further, since the wear at the base polymer passing portion is extremely small, the life of the base is extended, and the effect of reducing the manufacturing and management costs of the base can be obtained.

[Brief description of the drawings]

FIG. 1 is a front view (ejection side) of a die for a resin composition for molding of the present invention.

FIG. 2 is a sectional view taken along the line XX 'in FIG. 1 and schematically shows a polymer passing portion of the base.

[Explanation of symbols]

 1: Molding resin composition manufacturing die 2: Discharge hole 3: Polymer passing portion 4: Discharge hole exit

Claims (3)

[Claims] 1. A molding resin composition for producing a molding resin composition having a polymer passing portion, wherein the surface layer portion of the polymer passing portion and the vicinity of the outlet of the discharge hole are covered with vanadium carbide. Product manufacturing base. 2. An extruder for a resin composition, comprising a die for producing a resin composition for molding according to claim 1. 3. A method for producing a resin composition for molding, comprising discharging the molten resin composition melt-kneaded into a strand using the extruder according to claim 2.