JPS6050137B2 - Method for manufacturing cloth-reinforced elastomer sheet - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fabric-reinforced elastomer sheet for use in belt conveyors, flexible containers, etc., and a method for manufacturing said sheet, particularly suitable for use in applications where it comes into direct contact with food. be.

Conventionally, this type of sheet has generally been made of rubber or soft polyvinyl chloride resin.

However, these materials contain large amounts of compounded chemicals such as plasticizers and stabilizers, and when sheets made from these materials come into contact with food, these compounded chemicals may migrate, making them undesirable from a hygienic standpoint. do not have. Attempts have also been made to use polyurethane-based elastomers, but polyurethane is generally easily hydrolyzed by moisture, making it difficult to use in applications that come into contact with foods containing large amounts of water. others,
The use of thermoplastic synthetic resins such as nylon and polyethylene has been considered, but these synthetic resins lack flexibility and are not suitable as sheets for conveyor belts or flexible containers. Therefore, the present inventors conducted intensive research in order to economically supply sheets for conveyor belts and flexible containers that are hygienic and have excellent physical properties, especially for food transportation, and as a result, they arrived at the present invention. This is what I did. That is, in the present invention, a cylindrical fabric mainly made of polyester-based synthetic fibers is continuously fed into an extruder head, and a melted polyester elastomer is fed around the outer periphery of the fabric, and this is compressed to melt the polyester elastomer. forming an outer surface coating layer of the cylindrical fabric, and allowing a portion of the polyester elastomer melt to penetrate into the inner surface of the fabric through the gaps between the fibers of the cylindrical fabric;
This is crimped to form an inner coating layer of the melted polyester elastomer, so that the cylindrical fabric has a coating layer of the polyester elastomer on both the inner and outer surfaces, and the coating layer is formed of the fibers of the cylindrical fabric. This method of manufacturing a cloth-reinforced elastomer sheet is characterized by forming a cylindrical laminate that is integrated through a gap, then cutting the cylindrical laminate into pieces, and removing curvature in the width direction by heat pressing. The present invention will be described in detail below with reference to the drawings. FIG. 1 shows an embodiment of the present invention.

A cylindrical fabric 1 is made by weaving warp and weft yarns of polyester synthetic fibers into a cylindrical shape, and passes through the head 3 of the extruder 2 from the rear to the front.

The tubular fabric 1 is not treated with adhesive or the like.
The head 3 is as shown in FIG. 2, and consists of a head body 4 and a mandrel 5.
The cylindrical fabric 1 is configured to continuously pass through the gap between the two. The head body 4 is fitted with a truncated cone body 10 having a flange 9 in which a large number of holes 8 are annularly bored in a cylinder 7 having a synthetic resin injection port 6. A synthetic resin flow path is formed that passes through the outside of the truncated cone body 10 and reaches the outer surface of the cylindrical fabric 1 via the cylindrical body 7. The outer periphery of the shaped fabric 1 is coated with the synthetic resin.
The mandrel 5 is an annular body having a round bar 12 with an outer diameter approximately S equal to the inner diameter of the cylindrical fabric 1, and has a large number of long holes 13 at the tip thereof at positions facing the synthetic resin flow path. 14 and the ring body 1
Inner layer tie chips 15 provided at intervals on the inside of 4
is attached.

Thus, a synthetic resin flow path is formed that passes from the elongated hole 13 between the ring body 14 and the die tip 15 and reaches the inner surface of the cylindrical fabric 1 at the tip of the ring body 14.
The inner periphery of the cylindrical fabric 1 is coated with the synthetic resin at the tip. In addition, the mandrel 5 has a shaft 19
It is supported in a suitable manner at the rear via. In the present invention, a thermoplastic polyester elastomer is used as the synthetic resin.

The polyester elastomer melt 16 is passed through an extruder 2
The resin is extruded from the synthetic resin injection port 6 and press-fitted into the head 3 through the synthetic resin injection port 6. And melt 1 of the polyester elastomer
6 is supplied to the outer surface of the cylindrical fabric 1 through the hole 8 and between the truncated cone body 10 and the outer layer die chip 11, and a part of the melt is directly pressure-coated on the surface of the cylindrical fabric 1, It is extruded together with the cylindrical fabric 1 to form the outer surface coating layer 17. The remaining portion of the melt 16 passes through the gaps between the fibers of the cylindrical fabric 1, enters the ring body 14 through the elongated hole 13, and passes between the ring body 14 and the inner layer die chip 15. Said ring body 14
is supplied to the inner surface of the cylindrical fabric 1 while still in a molten state at the tip of the cylindrical fabric 1 , and is pressed to form the inner surface coating layer 18 of the cylindrical fabric 1 . The thus obtained cylindrical laminate 20 has the polyester elastomer coating layers 17 and 18 formed on both the inner and outer surfaces of the cylindrical fabric 1, and
, 18 are integrally connected through gaps between the fibers of the tubular fabric 1. After leaving the head 3, this cylindrical laminate 20 is cut open in its length direction by a knife 21.

In FIG. 1, the cylindrical laminate 20 that has come out of the head 3 is shown to be immediately cut open by the knife 21, but the cylindrical laminate 20 that has come out of the head 3 is left as is.
It may be rolled up and then cut open in a separate process. The cut-out laminate is spread out into a flat sheet 2'' by a nip roller 22, and taken off by a take-off device 23. The taken sheet 2' is the cylindrical laminate 2
Since it still retains its 0-shape and tends to return to its cylindrical shape, it is passed through the hot press roller 24.
After removing the curls and making it into a flat plate shape, it is wound into a coil shape by the winding device 25. To remove the curls, not only the heat press roller 24 but also a plate-shaped heat press or other suitable means may be used, and the heat press roller may also serve as the take-up device 23. The obtained belt can also be further surface-treated with fluororesin, silicone resin, etc., if necessary. In the present invention, polyester elastomer is used for the coating layers on both sides of the sheet.

Polyester elastomer is thermoplastic and easy to mold, has flexibility and comb-like elasticity, has appropriate strength and elongation, is chemically stable, and is resistant to water, chemicals, etc.
It has good resistance to heat, light, ozone, etc., and has excellent tear strength, bending resistance, abrasion resistance, and dimensional stability, and has stable performance over a wide temperature range of -70 to 140℃. demonstrate. Therefore, it is extremely suitable as a material for elastomer sheets for conveyor belts and flexible containers. Furthermore, polyester elastomer
In general, it has extremely low extractables and volatile components and has the above-mentioned excellent properties, so it is especially suitable for applications that come in direct contact with foods. The polyester elastomer used in the present invention includes an aromatic polyester such as polyethylene terephthalate, polypropylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polycyclohexane dimethylene terephthalate, polyethylene terephthalate/isophthalate as a hard segment, polyethylene ether glycol, Polybutylene ether glycol, polyethylene ether glycol ● Polyester polyether block copolymer with polyether as a soft segment such as polybutylene ether glycol copolymer, polyethylene adipate, polyethylene sebacate, polyethylene sebacate, etc. with the aromatic polyester as a hard segment. A polyester polyester block copolymer having an aliphatic polyester such as polybutylene adipate or polycaprolactone as a soft segment, a copolyester polyether having the above aromatic polyester as a hard segment, and a combination of the above polyether and aliphatic polyester as a soft segment. Copolymers, aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid and aliphatic dicarboxylic acids such as adipic acid, sebacic acid, azelaic acid, dimer acid, epsilon-caprolactone and ethylene glycol, propylene glycol, butylene glycol, Examples include random copolymers with diols such as neopentyl glycol and cyclohexanedimethanol. A mixture of two or more of these may be used. Further, it may be a product obtained by copolymerizing a small amount of a branched component such as trimethic acid or glycerin. This copolymer can also be stabilized by blocking its terminal carboxyl groups with an epoxy compound or the like. A particularly preferred copolymer is a polyester polyether block copolymer, and the proportion of the polyether segment component in the copolymer is preferably 10 to 8% by weight.

Moreover, the molecular weight of the polyether segment is 400 to
40(4) Especially preferably 800-2500. Further, the molecular weight of the copolymer is preferably at least 20,000 or more, particularly preferably 30,000 or more. or,
This polyester elastomer can be blended with a polyepoxy compound, polyisocyanate, etc. to increase the melt viscosity and further improve the physical properties of the resulting belt.

Also, depending on the application, flame retardants, crystallization promoters, organic or inorganic fillers, stabilizers, colorants, conductive agents, etc. may be added, but in applications that come into contact with food, Of course, it is preferable that no additives be added or that the amount added be minimal. On the other hand, in the present invention, the cylindrical fabric serving as the reinforcing layer is mainly made of polyester synthetic fibers, and filaments or spun yarns of the polyester synthetic fibers are woven, braided, or nonwoven.

This fabric may be made entirely of polyester-based synthetic fibers, or may be mixed with polyamide, aromatic polyamide, or polyvinyl alcohol-based synthetic fibers or natural fibers, but at least half of the total amount of fibers in the fabric It should be made of polyester synthetic fiber. Also, depending on the application, a small amount of conductive fiber may be mixed. The polyester is mainly composed of repeating units of alkylene terephthalate, especially ethylene terephthalate, and has an intrinsic viscosity (phenol/tetrachloroethane in a weight ratio of 3/2).
(measured at 0'C) is preferably 0.5 or more, particularly 0.6 or more.

In the present invention, the inner and outer covering layers are integrated through the gaps between the fibers of the cylindrical fabric, and since the elastomer and the cylindrical fabric are both polyester-based and have a high affinity, Cylindrical fabrics can be bonded extremely firmly without the use of adhesives.

Generally, in this type of laminated sheet, the elastomer coating layer and the fiber reinforced layer are usually bonded together with an adhesive.

However, when an adhesive is used, components in the adhesive migrate to the elastomer coating layer and even ooze out to the surface, which is a hygiene problem, especially in applications that come into contact with food. Moreover, no matter how good the elastomer or fiber is, if the adhesive has poor performance such as heat resistance or cold resistance, the performance of the entire sheet will ultimately be controlled by the performance of the adhesive, and it will not be sufficient. It becomes difficult to obtain a sheet with excellent performance. Especially heat resistance, cold resistance, water resistance,
At present, there is no adhesive that has properties comparable to polyester elastomers in terms of chemical resistance, flexibility, etc., and that can fully demonstrate these properties of polyester elastomers. Therefore, when using adhesive,
It is desirable to bond the elastomer and reinforcing layer. For this purpose, a combination of polyester elastomer and polyester synthetic fiber is optimal. However, the combination of polyester elastomer and polyester synthetic fiber does not always provide good adhesion.

For example, when polyester elastomer is coated on a fabric made of polyester synthetic fibers by extrusion lamination, the solidification speed of polyester elastomer is fast, so the polyester elastomer solidifies before it permeates into the fabric. Adhesive strength cannot be obtained.
Even when both sides of the fabric are coated, the elastomer only adheres to both sides of the fabric, and the elastomer does not integrate through the gaps between the fibers of the fabric, resulting in insufficient adhesion. Furthermore, in the lamination method using calender processing, since the softening point and melting point of the polyester elastomer are close to each other, it is difficult to control the temperature of the calender, and processing is virtually impossible. The extrusion lamination method and calendar lamination method as described above are
Although it is suitable for polyvinyl chloride resins that have a low melting point and softening point and a wide softening temperature range, this method cannot be said to be suitable for processing the polyester elastomer that is the object of the present invention. In the present invention, the melted polyester elastomer comes into contact with the cylindrical fabric under great pressure in the die of the extruder, and penetrates through the gaps between the fibers of the cylindrical fabric, resulting in an extremely large adhesive force. You can get it.

According to the experimental results, in the case of a sheet produced by the method of the present invention without using an adhesive, the adhesive force between the cylindrical fabric and the elastomer coating layer was about 5k9/Cm.

For comparison, a nylon tubular fabric was tested under the same conditions and the adhesive strength was approximately 2k9/C!
It can be seen that there is a large difference depending on the material of the cylindrical fabric and the elastomer, and therefore, in addition to a simple anchoring effect, there is also a wetting effect between the polyesters. Furthermore, in the case of polyester synthetic fiber fabric coated with polyester elastomer by calendar lamination or extrusion lamination, the adhesive strength is 1 kg/C7! Good adhesion as described above can only be obtained by combining the materials and processing methods of the present invention. It goes without saying that the processing temperature in the present invention must be higher than the melting point of the polyester elastomer, but in order to prevent the stretching effect of the polyester synthetic fibers constituting the tubular fabric from being lost and the physical properties to decrease, The temperature is preferably 20'C or more lower than the melting point of the polyester synthetic fiber.

Further, the cut sheet still has cylindrical curvature from molding and is curved in the width direction, so it is necessary to remove the curvature by heat pressing.

The temperature at this time is preferably within a range of 10'C or more lower than the melting point of the polyester elastomer and higher than the glass transition point. As described above, the process of the present invention is extremely simple, and a cloth-reinforced elastomer sheet can be obtained in one step. Moreover, unlike the lamination method, uneven portions do not occur on both edges of the sheet. ,
No material is wasted.

Moreover, since the cloth-reinforced elastomer sheet obtained by the method of the present invention has a polyester elastomer coating layer, it is safe and has no hygienic problems, and has appropriate elasticity, appropriate coefficient of friction, and excellent oil and water resistance. It has excellent properties such as chemical resistance, abrasion resistance, weather resistance, heat resistance, cold resistance, etc., and it also has excellent properties such as strong adhesion to reinforcing fabric without using an adhesive. It is excellent as a sheet for belts or flexible containers, and is particularly suitable for applications where it comes into direct contact with food. One embodiment of the present invention will be described below.

A cylindrical fabric with an inner diameter of 150T0L was woven using 1000 denier multifilament yarns made of polyethylene terephthalate fibers with an intrinsic viscosity of 0.75 as warp and weft yarns at a density of 60 warp and warp yarns per 10 CWI width, and polyester polyether elastomer was woven into the cylindrical fabric. (Toyobo Co., Ltd., Belprene Pl5OMl melting point 170°C) was coated at 200°C using the extruder shown in Figure 2 to obtain a laminate having a resin layer with an average thickness of 0.57T0n on both the inside and outside of the cylindrical fabric. Ta. Next, this cylindrical laminate was cut at a temperature of 150°C.
It is pressed between heated rolls to remove the curvature, and the thickness is 1.1T1r! ! A flat cloth-reinforced elastomer sheet of size L was manufactured. This sheet is 300T wide! Unl
It was cut out to a length of 2 m, and both ends were thermocompression bonded to each other at 200°C to form an endless belt. This belt has a diameter of 20C!
When a rotation test was performed by setting it between a pulley with a diameter of 50 cm and a tension of 10k9/10, no abnormality was observed even after rotating it for 10 cycles. For comparison, a belt was made using nylon 6 as the material for the cylindrical fabric and all other conditions were the same as in the previous example, and a similar test was conducted. A peeling phenomenon was observed.

In particular, the fibers of the fabric protruded from both edges of the belt, resulting in significant fluffing, making it unsuitable for use as a belt.

[Brief explanation of the drawing]

FIG. 1 is a front view showing an embodiment of the present invention, and FIG. 2 is a partially cut vertical section of the head in the embodiment. 1...Tubular fabric, 3...Head, 16
...Polyester elastomer, 17,18...
... Covering layer, 20 ... Fiber-reinforced synthetic resin cylindrical body (cylindrical laminate), 21 ... Knife, 24 ...
...heat roller.

Claims (1)

[Claims] 1. While continuously feeding a cylindrical fabric mainly made of polyester-based synthetic fibers into an extruder head, a melt of polyester elastomer is fed to the outer periphery of the fabric, and this is compressed to form an outer surface coating layer of the melt of polyester elastomer. At the same time, a part of the polyester elastomer melt is allowed to penetrate into the inner surface of the fabric through the gaps between the fibers of the cylindrical fabric, and is pressed to form an inner surface coating layer of the polyester elastomer melt. Molding a cylindrical laminate having a coating layer of the polyester elastomer on both the inner and outer surfaces of the cylindrical fabric, and in which the coating layer is integrated through the gaps between the fibers of the cylindrical fabric, and then cutting the cylindrical laminate open, A method for producing a cloth-reinforced elastomer sheet, characterized by removing curvature in the width direction by heat pressing.