JPH03162955A - Vulcanized rubber product and its manufacture - Google Patents

Abstract

PURPOSE:To manufacture a vulcanized rubber product bonded firmly by overlapping the polyurethane layer side of a base cloth formed by laminating polyurethane with the surface of an unvulcanized rubber composition in a manner of being in contact with, heating, pressurizing, vulcanizing the unvulcanized composition and bonding the polyurethane layer with the surface of the rubber composition. CONSTITUTION:A thin polyurethane layer 11 of a base cloth 1 composed of laminated polyurethane is overlapped with an unvulcanized rubber composition 2 in a manner of being in contact together. The unvulcanized composition 2 is heated, pressurized and vulcanized, and the polyurethane layer 11 is bonded with the surface of the rubber composition 2. Then, the top force 3 is opened and a base 10 entangled with flash rubber 12 is released while the temperature is high, and then a foil-like section (f) is entangled with the base cloth 10 to be separated completely from the rubber product. A vulcanized rubber product composed of a rubber layer and the polyurethane layer 11 bonded together firmly can be manufactured by the process.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a vulcanized rubber product and a method for manufacturing the same, a sole body of footwear having the vulcanized rubber product as a ground contact part, and a method of manufacturing footwear having this sole body. Regarding.

Prior art and its problems When vulcanized rubber is used, for example, as a ground-contact sole for footwear, it is necessary to strongly bond the vulcanized rubber material to a synthetic resin product such as semi-rigid polyurethane or a leather product. Therefore, it is necessary to have durability that can withstand large external forces.

Conventionally, the above-mentioned adhesive treatment involves first press-vulcanizing the vulcanized rubber material, then roughening the adhesive surface by puffing, chlorinating the surface, then applying a primer treatment, and then applying an adhesive treatment. This requires extremely complicated treatment steps such as . Even with such treatment, the adhesion was still unsatisfactory.

Therefore, in order to solve this problem,
In Publication No. 21, an unvulcanized rubber composition is loaded into a hollow mold, a perforated film of thermoplastic polyurethane having a specific composition and physical properties is loaded on at least one side of the composition, and then a certain heat pressure is applied. Three methods have been proposed in which the rubber products are laminated together to form a layer of polyurethane on the surface of the rubber product in order to increase the adhesive strength with semi-rigid polyurethane, synthetic resin products, etc.

However, when this manufacturing method is used, there are the following problems.

1). It takes an extra number of T to remove the flakes that occur on vulcanized rubber products during heating and pressurization. In particular, the temperature of this type of vulcanized rubber product obtained by heating and pressurizing in a mold is
Thickness 0.01mm ~ at the parting line of the mold
Since it has a thin foil shape of about 0.1 mm, its removal requires careful manual work with a sharp knife.

2〉. Because the surface of the polyurethane layer formed on the surface of the obtained vulcanized rubber product is smooth, the anchor effect does not work when it is bonded to synthetic resin products such as semi-rigid polyurethane or leather products. In order to increase the adhesive strength between the two, it is necessary to select an adhesive and perform complicated bonding work.

3). During heating and pressurization, when the unvulcanized rubber composition moves along the cavity in the mold and is shaped, tears occur in the portion of the polyurethane film that is in close contact with the rubber composition. In order to prevent this, it is necessary to make the film thicker than a certain level to give it toughness (thickness after molding is 0.02 to 1.00 mm). Vulcanized rubber products laminated with such thick films not only have the flexibility of the rubber inhibited, but also warp due to the difference in shrinkage rate between the polyurethane film and the rubber composition. easy.

4). Inside the mold, the polyurethane film is heated and pressurized while in direct contact with the mold, so rust, dirt, etc. on the mold surface adhere to the film surface and become cold traps that inhibit adhesion. .

Means for Solving the Problems As a result of intensive research to solve the problems listed in The rubber layer and the polyurethane layer can be firmly bonded by simply heating and pressurizing them, and in order to use the vulcanized rubber product obtained in this way as the ground-contact sole of footwear, primers, adhesives, etc. are required. It was discovered that good adhesion could be obtained simply by injection molding the polyurethane stock solution, without the need to use
The present invention has now been completed.

That is, the present invention relates to the following description.

■ When manufacturing a vulcanized rubber product that is an integrated lamination of vulcanized rubber and polyurethane, the polyurethane laminated base fabric is overlaid so that the polyurethane layer side is in contact with the surface of the unvulcanized rubber composition, and heated and pressurized. A method for producing a vulcanized rubber product, which comprises vulcanizing an unvulcanized rubber composition, adhering a polyurethane layer to the surface of the rubber composition, and then peeling off the base fabric.

■ A vulcanized rubber product obtained by the method described in item 1 above.

■ In a footwear molding method using the direct sole method, which involves suspending a shoelace from the last, combining it with a footwear bottom mold, and injecting a polyurethane stock solution into the cavity formed by these, the footwear is placed at a predetermined position in the bottom mold. - A method for molding footwear, characterized in that the vulcanized rubber product described in item 2 of item (E) is held and directly sawed to provide the rubber product as a ground-contact sole surface directly bonded to the polyurethane portion.

■ When molding the sole body of footwear using a polyurethane material, the vulcanized rubber product described in item 2 above is provided as a ground-contacting bottom surface directly bonded to the polyurethane part. Molding method.

The unvulcanized rubber used in the method for producing vulcanized rubber products of the present invention includes natural rubber, styrene-butadiene copolymer (SBR), acrylonitrile-butadiene copolymer (
Rubbers commonly used as molding materials for shoes and other rubber products include rubbers such as NBR), isoprene rubber (IR), and butadiene rubber (BR), and at least one of these rubbers is used.

These unvulcanized rubbers are mixed with known fillers, cross-linking agents, anti-aging agents, softeners, accelerators, activators, pigments, etc., as necessary during production, and used as unvulcanized rubber compositions. Ru. For example, fillers include calcium carbonate, finely divided silicic acid, and clay; crosslinking agents include sulfur and zinc white; anti-aging agents include phenolics such as styrenated phenol; and softeners include polymeric fatty acid esters. , higher fatty acids such as stearic acid, process oils such as naphthenic oils, factices such as black sub, jiso, DOP, etc.; as accelerators, thiazole accelerators such as 2-mercaptobenzothiazole and dibenzothiazyl disalhyde Activators include diphenyl dicyclo 8 hexylamine, polyethylene glycol, etc.; Examples of pigments include titanium oxide, red iron oxide, and various organic pigments. Can be done. The rubber content in the unvulcanized rubber composition is not particularly limited as long as it does not lose its function as a rubber product, and is usually about 20 to 90% by weight.

The base fabric in the base fabric laminated with polyurethane used together with the unvulcanized rubber refers to, for example, a woven fabric, a nonwoven fabric, or a knitted fabric made of fibers such as natural fibers and synthetic fibers. Moreover, the polyurethane laminated on the base fabric in advance is a polyurethane obtained by reacting at least one of each of polymer glycols, organic isocyanates, and chain extenders having an average molecular weight of 1,000 to 4,000.

Examples of the polymer glycols include polyether diols such as polyethylene adipate glycol, polypropylene adipate glycol, polybutylene adipate glycol, polyhexamethylene adipate glycol, copolymerized glycols thereof, and polytetramethylene glycol. Examples of the isocyanates include tolylene diisocyanate, diphenylmethane-4,4'-diisocyanate-1-, xylylene diisocyanate, naphthylene diisocyanate, diphenylmethane-4,4'-diisocyanate hydrogenate, and xylylene diisocyanate hydrogenate. , hexamethylene diisocyanate, and isophorone diisocyanate. Further, examples of chain extenders include low molecular weight diols having two active hydrogen atoms, low molecular weight diamines, and the like.

-1 When synthesizing the polyurethane described in Section 2, polymer glycols, organic isocyanates, and chain extenders are blended so that the resulting polyurethane has suitable heat-melting properties and adhesion to the rubber composition described in L. ratio can be selected. Factors that determine the properties of polyurethane include the isocyanate group/active hydrogen group ratio, the urethane group content ratio, the aromatic ring content ratio, and the like. In the present invention, the above blending ratio is mainly determined by adjusting the isocyanate group/active hydrogen group, and by blending so that the isocyanate group/active hydrogen group ratio is preferably about 0.90 to 1.02, Good polyurethane can be obtained.

When the above polyurethane is used for lamination on the base fabric, it is made into a film in advance, and the thickness of the film is determined by the adhesive strength as the ground sole surface of the vulcanized rubber product of the present invention during injection molding of footwear soles using the polyurethane stock solution. There is no particular restriction as long as the value can be maintained, and the value before heating and pressure molding is usually 0.01.
mm or more, preferably about 0.01 to 0.05 mm.

The method for laminating the polyurethane onto the base fabric is not specified, but for example, a solvent-based adhesive having the same or similar composition may be applied to a film of polyurethane and then laminated onto the base fabric. Further, at this time, the surface of the base fabric may be brushed to improve entanglement with polyurethane.

The base fabric laminated with polyurethane in the method for producing a vulcanized rubber product of the present invention includes, in addition to those obtained as described above, urethane-based synthetic leather commonly used in this field.

The present method for manufacturing vulcanized rubber crystals will be described in detail with reference to FIGS. 1 to 4 showing one example thereof.

The unvulcanized rubber composition (2) is weighed and loaded in advance into the lower mold (4) according to a conventional technique in an amount sufficient to produce rubber flakes, and then a base layer with polyurethane laminated on two sides of the unvulcanized rubber composition (2) is loaded. cloth (1
A thin polyurethane layer (11) of ) is placed in contact with the rubber composition (2) (FIG. 1). When superposing the polyurethane laminated base fabric (1) and the rubber composition (2), a suitable primer may be applied to the polyurethane surface of the base fabric in advance.

12 Close the ten molds (3) and set the mold temperature to about 120'C to 180C and the press pressure to 100kg/c [lI2 to 200kg/c.
The polyurethane thin layer (11) of the base fabric is adhered onto the rubber composition (2) by applying heat and pressure for about 3 to 10 minutes at about m2. At this time, the excess rubber composition (2) and polyurethane thin layer (11) pass through the parting lines of the upper and lower molds (3) and (4) to form burr rubber (12) in the grooves (6), and the parting Bali rubber (
12) Thickness connected to 0.01mm ~ 0.1+am
A fairly thin foil-like part (f) is formed (Fig. 2).

After opening the upper mold (3), press the burr rubber (
When the entangled base fabric (10) of 12) is peeled off, the foil-like portion (f) becomes entangled with the base fabric (10) and is completely separated from the rubber product (FIG. 3).

The base fabric (1
The surface of 0) is transferred and fine irregularities (5) are formed (
Figure 4).

In addition, if the engraving of the design normally provided on the lower mold (4) is slow, the rubber product can be easily taken out from the lower mold (4) by grasping the base fabric entangled with the burr rubber (12). Sometimes.

In such a case, the desired rubber product can be obtained by immediately grasping and peeling off the end of the rubber product and the base fabric entangled with the burr rubber (12) while taking it out.

The vulcanized rubber product obtained as described above becomes practical by being used, for example, as the ground contact sole of footwear. In other words, because the vulcanized rubber product has fine irregularities on its polyurethane surface, when it is provided as a ground-contact sole surface of footwear by injection molding of a footwear sole using a raw polyurethane solution, it becomes anchored to the polyurethane layer of the footwear sole body. It works well and can be installed without using any primer or adhesive.

A method of using the above-mentioned vulcanized rubber product as a ground contact sole of footwear will be described in detail with reference to FIG. 5, which shows one embodiment thereof.

In Figure 5, the last part (21) is fitted with a cover (24).
This is combined with a Zide mold (22) and a bottom mold (23) for forming the bottom of clothing, and explains the Direct 1 Solink method in which the polyurethane stock solution is injected from the injection port (a) into the cavity formed by these. be. As is clear from FIG. 5, the polyurethane thin layer of the vulcanized rubber product of the present invention is received and held at a predetermined position in the bottom mold (23) facing in two directions, and in this state, it is inserted into the cavity as usual. Inject polyurethane stock solution.

At this time, there is no need to apply a primer, adhesive, etc. to the vulcanized rubber product as in conventional methods. By carrying out the following processing in a conventional manner, footwear having the vulcanized rubber product of the present invention as a ground-contacting sole can be obtained.

15 In addition, instead of using the direct sawing method as described above, footwear can also be obtained by forming the sole body of the footwear and then pasting it together with the shoelace and the midsole. The sole body of this footwear can be molded in a conventional manner using a mold for molding a footwear sole.

For example, as shown in FIG. 6, the polyurethane film of the vulcanized rubber product of the present invention is received and held in a predetermined position of the lower mold (32) with the polyurethane film facing upward, and the upper mold (3]) and the lower mold (32) By injecting a polyurethane stock solution into the cavity formed by combining the above and then molding in a conventional manner, a sole body of footwear having the vulcanized rubber product of the present invention as a ground-contact sole can be obtained. In this case as well, there is no need to apply a primer, adhesive, etc. to the vulcanized rubber product, as described above.

Effects of the Invention The present invention has the above-described structure and operation, and therefore brings about the following effects.

l). In the manufacturing method of vulcanized rubber products, the foil-like part made of rubber and polyurethane that occurs in the partin 16 grain part gets entangled with the base fabric together with the burr rubber when the base fabric is peeled off, and is completely separated from the rubber product. However, the thickness of 0.01 mm to 0.1 mm, which was a big problem in the conventional technology.
It is possible to remove a certain amount of foil-like burr very easily.

2). In the vulcanized rubber product of the present invention, the surface of the base fabric is transferred to the surface of the polyurethane thin layer adhered to the rubber, forming fine irregularities. When used in applications such as semi-rigid polyurethane or other synthetic resin products or leather products, the anchor effect works, resulting in a marked improvement in the adhesive strength of both materials, eliminating the need for traditional adhesive selection and complexity. It is possible to omit the adhesive work.

3). Even if the unvulcanized rubber composition moves along the cavity in the mold during heating and pressurization in the manufacturing method of vulcanized rubber products, the thin polyurethane layer in close contact with the rubber composition is supported by the base fabric. Because of this, there is no chance of tearing, even if it is thin. Therefore, there is no need to make the polyurethane layer thicker than necessary to provide toughness as in the past. Moreover, as a result, the flexibility of the vulcanized rubber product after molding is not inhibited, and the product does not warp due to the shrinkage rate of the polyurethane thin layer.

4). During heating and pressurization in the manufacturing method of vulcanized rubber products, the polyurethane thin layer is protected by the base fabric in the mold, so it does not come into direct contact with the mold. Therefore, dirt, dirt, etc. on the surface of the mold will not adhere to the surface of the thin polyurethane layer and inhibit adhesion.

5). During heating and pressurization in the manufacturing method of vulcanized rubber products, the texture of the base fabric acts as a gas vent, so the contact surface between the molding die and the polyurethane thin 11゛4 or unvulcanized rubber composition is There is no formation of air or gas pockets. Furthermore, since the base fabric is present, the mold can be removed very smoothly.

EXAMPLES Hereinafter, the present invention will be explained in more detail by giving examples.

Example 1 When manufacturing athletic shoes using the direct sole method of polyurethane foam, normal processing was carried out using the compounding ratios listed in Table 1 A in order to adhere a rubber piece to the treading part of the sole of the shoe, which undergoes the most wear. A sheet of unvulcanized rubber composite having a thickness of 5 mm was obtained by this method.

A piece of the unvulcanized rubber composition (2) having a capacity large enough to release the rubber was cut from this sheet and loaded into a vulcanizing hollow-type downstream mold (4). A thin layer of polyurethane layer (11) of commercially available urethane synthetic leather (“Sof1 Vile 510-P” manufactured by Komatsu Seiren Co., Ltd.) (1) is coated with a thin layer of brimer having the composition shown in Table 2 in advance, and then a lower layer is applied. Cut it into a size large enough to cover the rubber composition piece (4), and overlap it so that the primer coated side is in contact with the -J1 rubber composition piece (2), so that the urethane-based synthetic leather is on the top side. Then, the mold (3) was closed and the rubber was vulcanized for 5 minutes at a mold temperature of 150° C. and a press pressure of 150 kg/c [lI2].

At this time, the excess unvulcanized rubber composition (2) is removed from the upper and lower molds (
3) Pass through the parting line in (4) and insert the Bali rubber (1
2) occurred. In addition, at the parting line portion, the rubber composition (2) and the polyurethane thin Jd (11) were 0.
The foil-like portion (f) became extremely thin with a thickness of 0.1 mm or less, and was entwined with the base fabric (10) and continuous with the Bali rubber (12) (see FIG. 2).

After opening the second mold (3), I was able to grab the urethane synthetic leather Bali rubber (12) before the temperature of the product dropped, and easily peel off the base fabric (10) that was continuous with it. (
Figure 3).

At this time, the foil portion (f) is entangled with the base fabric (10) and completely separated from the rubber product, and the polyurethane thin layer (11) is evenly laminated and bonded on the rubber composition 20 product (2). was left behind. In addition, a thin layer of polyurethane (11
), fine irregularities (5) corresponding to the irregularities of the base fabric (10) were transferred (FIG. 4). In this way, the desired vulcanized rubber pieces were obtained.

This rubber piece was held in a predetermined position in a shoe sole mold, and a foaming urethane solution commonly used in the production of athletic shoes by the Directrec 1 soleing method was poured into the mold and cured according to a conventional method. Using this as a sample, the peel strength of both materials was measured using the test method specified in JIS K6301, and the result was 3.
The value was 5 kgf/cm and the abrasive material was destroyed.

Example 2 Using the rubber formulation listed in Table 1 B, an unvulcanized rubber composition was loaded into a vulcanization mold according to Example 1, and separately,
On the polyurethane side of the polyurethane laminated cloth, thermoplastic polyurethane mainly composed of polycaprolactone glycol, diphenylmethane 4,4-diisocyanate and ethylene glycol is laminated to a thickness of about 0.03 mm on one side of fine cotton twill #1300. A primer having the composition shown in Table 2 was applied thinly, and press vulcanization was performed in the same manner as in Example 1, and the base fabric was peeled off to obtain a vulcanized rubber piece.

Next, use a commercially available urethane adhesive (“No Tape #3050”) to adhere this vulcanized rubber piece to the vulcanized rubber bonding location on the bottom of the polyurethane unit 1 sole, which had been previously foam-cured. (manufactured by Kogyo ■) mixed with 5% Desmodur RF in a conventional manner.

When the peel strength between both materials was measured using the test method specified in JIS K6301, it was 3. 2kgf/cm
, and material failure occurred.

Example 3 Using the rubber composition listed in Table 1 A, an unvulcanized rubber composition was loaded into a mold for vulcanization according to Example 1, and a urethane laminated fabric was prepared. Leather (“Lamoc 50
00 (manufactured by Daiichi Kasei ■) was brought into direct contact with the unvulcanized rubber composition as it was, and press vulcanized in the same manner as in Examples 1 and 2 above to obtain vulcanized rubber pieces.

Next, in the same manner as in Example 1, this vulcanized rubber piece was cast with a foamable urethane stock solution and cured. Using this as a sample, JI
As a result of determining the peel strength of both materials until the end using the test method prescribed in SK6301, the value was 4.3 kgf/c+n, resulting in material failure.

Example 4 Using the rubber composition shown in Table 1 C, the urethane surface of the urethane laminated cloth described in Example 2 was brought into direct contact with the surface of the unvulcanized rubber composition, and the following press vulcanization was performed in the same manner. I got a piece of rubber.

Next, in the same manner as in Examples 1 and 3, a urethane stock solution was cast into the vulcanized rubber piece by a conventional method and cured.

Peel strength between both materials based on JIS K6301 23 is 4. It showed 1 kgf/c... and the control was destroyed.

24 Solution polymerization SBR NBR Liquid NBR IR BR Sulfur zinc 7' 20.0 17.0 29.0 2360 1.3 1.8 67.0 4.0 25 Note) 1> Mercap 1/penzothiazole 45% by weight Dibenzothiazole disalhide 45% by weight Tetramethylthiuram monosulfide 10% by weight 2) Diphenyl dicyclohexylamine (“Acting SL” manufactured by Yoshitomi Pharmaceutical ■) 3) Why 1 Carbon “Nip Seal VN3” Mouth manufactured by Silica ■4) “NA2
4” Made by Idemitsu Oil■ 5> “Struktor WB” West German SCHILL&SE
Manufactured by ILACHER GmbH 6) Sulfur factice 2 Table 1 Unvulcanized rubber of Table A 100 Toluene 100 MEK 150 (Single: parts by weight)

[Brief explanation of the drawing]

FIGS. 1 to 4 are explanatory diagrams showing, step by step, the production of a vulcanized rubber product according to an embodiment of the present invention using cross-sectional views. FIG. 5 is a longitudinal sectional view showing a situation in which direct 1 sorting is performed. FIG. 6 is a longitudinal cross-sectional view showing a situation in which a sole is molded by injection molding. (1)...Polyurethane laminated base fabric (2)...Rubber composite material (3), (31)...Upper mold (4), (32)...Lower mold 27 (5) ... Fine irregularities (6) ... Grooves (10) ... Base fabric (11), (2), (36) ... Thin polyurethane layer (12) ... Bali rubber (21) ... Last (22)...Side mold (23)...Bottom mold (24)...Flip cover (25)...Middle sole (26), (27), (33), (34)... Vulcanized rubber (28), (35)...Polyurethane (a)...Injection port (f)...Foil-shaped part (above) 28

Claims (4)

[Claims] (1) In manufacturing a vulcanized rubber product in which vulcanized rubber and polyurethane are laminated and integrated, the polyurethane layer side of the base fabric laminated with polyurethane is placed in contact with the surface of the unvulcanized rubber composition, and heated. A method for producing a vulcanized rubber product, which comprises vulcanizing an unvulcanized rubber composition under pressure, adhering a polyurethane layer to the surface of the rubber composition, and then peeling off the base fabric. (2) A vulcanized rubber product obtained by the method according to the first claim. (3) In a footwear molding method using the direct sawing method, in which a shoelace is hung on the last, this is combined with a footwear bottom molding mold, and a polyurethane stock solution is injected into the cavity formed by these, a predetermined position of the bottom mold is used. A method for molding footwear, characterized in that the vulcanized rubber product according to claim 2 is held and directly sawed to provide the rubber product as a ground-contact sole surface directly bonded to the polyurethane portion. (4) A sole body of footwear characterized in that, when the sole body of the footwear is molded using a polyurethane stock solution, the vulcanized rubber product according to claim 2 is provided as a ground-contacting sole surface directly bonded to the polyurethane portion. molding method.