JP2535129B2 - Cushion material for molding press and method of manufacturing the same - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cushioning material for molding press used for press molding of synthetic resin laminates, printed circuit boards and the like.

[0002]

2. Description of the Related Art Heretofore, as a typical example of this type of press cushion material, a non-woven material and a heat-resistant papermaking material have been known.

As the former non-woven fabric, for example, as seen in JP-A-55-101224, batts of aromatic polyamide fiber are laminated with a base fabric into a plurality of layers and they are joined and integrated by needle punching, Moreover, those which have been subjected to heat treatment finish are known.

As the paper-made paper, there are many examples such as Japanese Examined Patent Publication No. 2-60799, Japanese Utility Model Publication No. 62-60300, Japanese Unexamined Patent Publication No. 63-60715, and Japanese Utility Model Publication No. 63-75329. As can be seen, a wet paper is made from an aqueous slurry in which mainly inorganic fine fibers and a pulp material of a heat-resistant aromatic polymer are mixed, and the necessary number of the wet paper is laminated and dehydrated and dried. The most commonly known one is the one that is integrated.

[0005]

However, the above-mentioned conventional non-woven cushion materials having excellent initial cushion properties due to the three-dimensional orientation of the fibers, when repeatedly used under high temperature and high pressure, Cushioning properties decrease with a remarkable decrease in thickness, and the heat conduction speed also changes, resulting in non-uniform heat distribution, which has the essential drawback of a short service life. In addition, the uneven thickness distribution, that is, the uneven weight is likely to cause uneven cushioning and uneven heat transfer rate, which may cause adverse effects such as unevenness on the surface of the molded laminate. It was

On the other hand, the paper-made cushion material has the advantages that it can be manufactured with a uniform basis weight, there is little unevenness in thickness and change in thickness over time, and that it has good heat resistance. However, on the other hand, it is inferior in the cushioning property originally required for the cushioning material. Therefore, the pressure compensation due to the unevenness of the hot platen, the unevenness of the end plate, the flow of the laminated plate, etc. cannot be sufficiently performed, and as a result, the appearance defect such as the occurrence of voids due to insufficient pressure in the laminated plate is likely to occur. It had drawbacks.

Therefore, an object of the present invention is to allow the conventional cushioning material made of heat-resistant paper to retain its advantages and to improve its cushioning characteristics. More specifically, a cushioning material for a molding press, which has less uneven weight per unit area and less change in thickness over time, has good cushioning properties, has excellent compression restoring force, and can significantly increase the service life. The purpose is to provide.
Furthermore, it aims at providing the suitable manufacturing method of such a cushioning material.

[0008]

In order to achieve the above object, the present invention utilizes the superior weight accuracy and dimensional stability of paper making, while at the same time providing the low cushioning property inherent in the paper making during paper making. This is improved by dispersing and containing an elastic powder.

That is, the cushioning pad for molding press according to the present invention comprises an organic fiber and / or an inorganic fiber, and a vulcanized material.
It is characterized in that it is made of a papermaking paper which contains elastic powder having a JIS A hardness of 20 to 98 degrees as a main component as a main component, and the elastic powder is uniformly dispersed throughout. It is a thing.

As a component of the papermaking paper, that is, a papermaking material, in addition to the above-mentioned essential fibers and elastic powder, if necessary, a polymer pulp-like substance and a binder are used in any selection or combination.

A papermaking paper made from a polymer pulp-like substance and an elastic powder, which does not contain the above fibers, was also examined. However, since such papermaking paper has a poor cushioning property, a cushion for a molding press is used. As a result of the experiment, it was found that it was not suitable for wood.

In the method for producing a cushioning material for molding press according to the present invention, an elastic body having an average particle diameter of 250 μm or less is obtained by adding a granular or fibrous solid pulverizing medium to an elastic body compound and kneading and pulverizing. A powder is prepared, the elastic powder is dispersed in an aqueous slurry obtained by disaggregating a paper-making paper material containing at least organic fibers and / or inorganic fibers, and the elastic powder is uniformly dispersed in the aqueous slurry from the aqueous slurry. It is characterized by being made into paper.

Still another feature of the present invention will be successively clarified by the detailed description of the configuration described below.

[0014]

[Detailed Description of Structure] (Fiber Material) The fiber used as an essential component of the papermaking paper may be either an organic fiber or an inorganic fiber,
Alternatively, they may be mixed and used.

Examples of usable organic fibers include polyamide fibers, aromatic polyamide fibers, phenol fibers, polyphenylene sulfide fibers, polyimide fibers, polyamideimide fibers, polyester fibers, aromatic polyester fibers, polyarylate fibers, and fluorine fibers. Can be mentioned. Further, as the inorganic fiber, glass fiber, slag wool fiber, rock wool fiber, carbon fiber,
Examples thereof include silica fiber, silicon carbide fiber, alumina fiber, alumina silicate fiber, wollastonite fiber, zirconia fiber, and metal fiber. Among these, slag wool fibers and rock wool fibers can be preferably used from the viewpoint of price and heat resistance, and aromatic polyamide fibers can be preferably used from the viewpoint of weight and heat resistance. It is recommended to select and use them accordingly.

Fiber diameter of 1 to 30 μm, regardless of organic or inorganic,
Fibers with fiber lengths in the range 300 to 15,000 μm should be used.

When the fiber diameter is less than 1 μm, the drainage is poor, making thick paper is difficult and not only unfavorable in terms of the cushioning material manufacturing efficiency, but also unfavorable in cushioning property. On the other hand, when it exceeds 30 μm, the entanglement of fibers in the papermaking paper is insufficient, and the paper interlaminar peel strength becomes particularly weak.
The service life is shortened. Most preferred fiber diameter is 5 to 2
It is about 0 μm.

When the fiber length is less than 300 μm, the entanglement of the fibers is insufficient, and the transverse rupture strength of the papermaking paper and eventually the cushioning material is weakened to deteriorate workability and service life. On the contrary, when the fiber length is longer than 15,000 μm, pills of fibers are likely to be formed at the time of disaggregation and the texture of the surface of the papermaking paper is deteriorated. Further, the weight per unit area is likely to be non-uniform, and the thickness accuracy is likely to deteriorate. The preferred fiber length is in the range of approximately 1,000 to 7,000 μm.

(Elastic Body Powder) The elastic body powder imparts good cushioning properties to the papermaking paper. Therefore, it must possess desirable elasticity in itself. Therefore, from this point of view, the hardness after vulcanization is JIS
An elastic material having a hardness of A20 to 98 degrees is used. If the hardness is less than 20 degrees, the amount of compressive deformation of the cushion material becomes excessive and the elastic restoring force becomes poor, which is not preferable. Further, an elastic powder having a temperature of more than 98 degrees is insufficient in elasticity of itself and cannot provide good cushioning properties to the cushion material. The most preferable hardness range is approximately 60 to 80 degrees. The elastic powder may be of any type as long as it has the above hardness.
It may be a rubber material or a thermoplastic resin elastomer material. Examples of the former include, for example, natural rubber, isoprene rubber, styrene butadiene rubber, polybutadiene rubber, chloroprene rubber, acrylonitrile butadiene rubber, hydrogenated nitrile rubber, butyl rubber, ethylene propylene rubber, polyurethane rubber, silicone rubber, fluorine rubber, chlorosulfone. Polyethylene, chlorinated polyethylene, acrylic rubber, epichlorohydrin rubber, polysulfide rubber, propyleneoxy rubber, ethylene acrylic rubber, ethylene vinyl acetate copolymer, polynorbornene rubber, alfin rubber and the like can be used. Examples of the latter elastomer material include polystyrene-based, polyolefin-based, polyurethane-based, polyester-based, polyamide-based, vinyl chloride-based, 1,2-
Various materials such as polybutadiene-based, polyisoprene-based, chlorinated polyethylene-based, and fluororubber-based materials can be used.

Among the various elastic materials described above,
Especially when the cushioning material is used for hot pressing, an elastic material having excellent heat resistance should be selected and used.
As the heat resistant elastic material, hydrogenated nitrile rubber, butyl rubber, ethylene propylene rubber, silicone rubber, fluoro rubber, acrylic rubber, ethylene acrylic rubber, and alfin rubber can be preferably used among rubber materials. Among the thermoplastic elastomer materials, polyolefin-based, polyester-based, polyamide-based, and fluororubber-based materials can be preferably used.

The particle size of the elastic powder also greatly affects the performance of the cushion material. Thus, the average particle size is 20 to 2
A range of 50 μm should be used. If the average particle size is less than 20 μm, the elastic powder is buried between the fibers of the papermaking paper, and good cushioning properties cannot be obtained. In order to prevent this, the elastic powder should have a particle diameter several times larger than the diameter of the fiber. However, when the average particle size is larger than 250 μm, precipitation of elastic powder or uneven distribution due to water flow in the head box occurs in the paper making process, which causes unevenness of cushioning property in paper making. It is not preferable because unevenness and poor texture of the paper surface occur. The most preferred particle size range is an average particle size of 30 to 90 μm.

The elastic powder having a particle size range as described above can also be produced by pulverizing the elastic compound with a known pulverizing method such as mechanical pulverization or freeze pulverization. However, the mechanical crushing has a particle size of 200 to 400 μ.
250 μm required for the present invention, which can only pulverize in the range of m
It is not preferable because the yield of the following fine particle powder is poor. On the other hand, freeze pulverization is most suitable for the present invention, 30 to 90μ.
Compared to the particle size range of m, the particle size is slightly larger, 100-250
Since it can only grind in the range of μm, it cannot be said to be the best method from the viewpoint of securing the most favorable texture for papermaking.

The method of kneading and pulverizing is most suitable for the above two pulverizing methods. That is, this method is a method in which a solid pulverizing medium capable of imparting a shearing force to an elastic compound is mixed with a liquid anti-adhesive agent, and kneaded with a kneader, an internal mixer or other closed kneader. By appropriately selecting the shape of the grinding medium and the kind of the anti-adhesive agent, it is possible to grind fine particles having a particle diameter of 10 to 250 μm, and it is also preferable in terms of grinding cost.

The crushing medium may be powdery or fibrous as long as it is a solid substance capable of imparting a shearing force to the elastic compound, but has a size that does not give a reinforcing action to the elastic body. It is necessary to be. For this reason, a powder-granular material having a particle diameter of 2 to 100 μm and a fibrous material having a fiber diameter of 2 to 100 μm can be easily miniaturized together with the elastic body by the shearing force of the kneader. The brittle material that can be used should be used.

As the grinding medium, specifically, sugar powder,
Water-soluble particles such as sodium chloride powder may be used. In this case, after the production of the elastic powder, it becomes possible to dissolve the pulverizing medium by dissolving it in water before or during papermaking. However, most commonly and preferably, as the grinding medium, glass fibers, slag wool fibers, rock wool fibers, fibrous materials such as silica fibers, or glass beads, silica powder, coal powder, calcium carbonate, ferrite powder, etc. Granules are used. The fibrous material is easily finely pulverized together with the elastic body by kneading and pulverizing, and the fibrous material becomes fine particles having a fiber length similar to the particle diameter of the elastic body powder, that is, 10 to 250 μm. When fibrous or granular materials are used, most of them enter into or adhere to the rubber particles, and the other parts are present in fine particles in the papermaking paper. In addition, the use of hollow glass beads among the granules helps to reduce the weight of the papermaking paper and suppress thermal conductivity, and it is easy to obtain those with a uniform particle size, so the particle size of the elastic powder is uniform. Which is advantageous.

The compounding amount of the grinding medium is preferably 40 to 400 parts by weight with respect to 100 parts by weight of the elastic compound. If it is less than 40 parts by weight, the crushing action of the elastic compound becomes insufficient, and sufficient miniaturization cannot be achieved. On the other hand, if the amount is too much over 400 parts by weight, the elasticity and cushioning property of the papermaking paper will be insufficient due to the relative decrease in the amount of elastic powder.

At the time of kneading and pulverization, a liquid anti-adhesive agent is added if necessary. The liquid anti-adhesive agent adheres to the cut surface of the elastic body crushed by the crushing medium, prevents re-adhesion of the elastic body, and promotes fine pulverization. As the liquid anti-adhesive agent, a non-aqueous surfactant such as silicone oil or fluorine oil, or a water-soluble surfactant is used. The amount added to the elastic member Konpaun de 1 00 parts by weight, 3
It should be less than or equal to parts by weight. If it is used in excess of 3 parts by weight, not only adverse effects such as foaming may occur at the time of papermaking but also the anti-adhesion agent may exude during use of the paper after papermaking.

(Polymer pulp-like substance) In addition to the above-mentioned fiber material and elastic powder as the essential components, it is preferable to add a required amount of polymer pulp-like substance to the papermaking material. Here, the polymer pulp-like substance means a polymer raw material that is mechanically or chemically refined to form a polymer fibrous aggregate, and all or part of the polymer is fibrillated. It is a nest-shaped branch. Therefore, the addition of such a pulp-like substance not only increases the cushioning property of the papermaking paper, but also effectively functions to improve the mechanical strength of the papermaking paper due to the binding action of the fibrillated fiber portion.

Specific examples of the polymer material of the pulp-like substance include cellulose pulp as a natural material and aromatic polyamide, aromatic polyester, polyamide, polyimide, polyamideimide, polyester, polyolefin, polycarbonate, fluororesin as a synthetic material. , Phenol, polyacetal, modified polyphenylene ether, polybutylene terephthalate, ultra high molecular weight polyethylene, polysulfone, polyether sulfone, polyphenylene sulfide, polyarylate, polyetherimide, polyetheretherketone, liquid crystal polymer, and modified resins thereof and these Can be a mixture of.

The blending amount of the polymer pulp-like substance is such that the above-mentioned organic and / or inorganic fibers, the polymer pulp-like substance and
50vol for the combined volume of elastic powder
% Or less, preferably in the range of 5 to 20 vol%. If a large amount of pulp-like substance is added to the content of more than 50 vol%, the cushioning property will be deteriorated and the cost will be increased.

The pulp-like substance has a drainage value of 1
It is preferable to use the one adjusted to the range of 100 seconds. If the drainage value exceeds 100 seconds, it is difficult to make a thick wet paper at a time, and it is necessary to stack a plurality of thin wet papers to obtain a paper having a required thickness. This is not preferable in terms of papermaking efficiency.
Here, the above-mentioned drainage value as used in the present specification means that a pulp-like substance is adjusted to a 0.3% aqueous dispersion (20 ° C.), and 1 liter of this slurry is taken to prepare a 78-mesh slurry at the bottom. When transferred to a cylindrical container having an inner diameter of 102 mm and covered with a wire net, the time required for obtaining 500 ml of the filtrate is expressed in seconds.

(Binder) The binder is effective for increasing the delamination strength of the papermaking paper, but on the other hand, it raises the temperature rising rate when the papermaking paper is used as a cushioning material and reduces the elastic restoring force. Therefore, even if added, it should be used in a relatively small amount range. Therefore, the total volume of the organic fiber and / or inorganic fiber, the polymer pulp-like substance, and the elastic powder is 100.
It should be used in the range of at most 10 vol% with respect to vol%, and preferably in the range of 7 vol% or less.

Specific examples of the binder include, for example, epoxy resin type, silicone resin type, phenol resin type,
A thermosetting resin such as an acrylic resin can be used. The form may be granular, latex or emulsion.

(Papermaking) Papermaking of the papermaking paper with the above-mentioned papermaking material can be carried out by a conventional method. That is, the elastic powder is uniformly dispersed in an aqueous slurry obtained by mixing and disintegrating fibers and a polymer pulp-like substance to be added if necessary, and a fourdrinier type,
A thick wet paper is preferably made into a paper using a paper making machine such as a cylinder type or inclined wire type machine, and dehydrated and dried to produce a thick paper. Alternatively, the required number of wet paper sheets formed into thin sheets may be stacked and dehydrated and dried under heat and pressure.

The amount of the elastic powder blended is 10 to 95 based on the combined volume of the organic fibers and / or inorganic fibers, the polymeric pulp-like substance, and the elastic powder.
It should be set to vol%. If this amount is excessively mixed in excess of 95 vol%, the elastic restoring force is improved, but the compression resistance and mechanical strength are deteriorated, which is not preferable. On the other hand, if it is less than 10 vol%, the desired good cushioning property and elastic restoring force cannot be realized. A more preferable range is 40 to 92 vol%. However, as shown in the examples described later, when the papermaking paper is required to have an adhesive function for laminating and adhering to another papermaking paper when it is manufactured into a cushioning material, it is relatively often used. It is advantageous to disperse the elastic body powder of 1., and when it is used exclusively for the cushion function, a relatively small amount of elastic body powder is dispersed and contained. Preferably. In the former papermaking paper for adhesion, the most preferable blending amount of elastic body powder is 50 to 92.
vol%, and 40-for paper made of cushions
It is 65 vol%.

(Production of Cushion Material) The papermaking paper produced as described above may be used alone as a cushion material, but generally, a plurality of paper sheets are stacked and laminated by heating and pressurization. It is put to practical use by forming it to a thickness, and further laminating and adhering a surface layer material made of a releasable material on both upper and lower surfaces thereof. As the surface layer material, any known surface layer material, for example, woven fabric, non-woven fabric, paper, or any of these impregnated or coated with a modifier, or a plate, sheet, film or metal foil made of a heat resistant synthetic resin. Etc. can be used.

[0037]

【Example】

Example 1 Rockwool fiber as a papermaking material and EPDM (ethylene propylene terpolymer) obtained by a freeze pulverization method
An elastic powder consisting of, a pulp-like substance, and a binder are used as main components.

The elastic powder was manufactured by the following method. That is, the compounding materials shown in Table 1 below were kneaded with a batch type internal mixer, pelletized with a pelletizer, and frozen and pulverized with a high-speed rotary fine pulverizer (turbo mill). At the time of freeze-grinding, talc was added as a solid anti-adhesive at a ratio of 11.3 parts by weight to 100 parts by weight of the compounded material. Then, the obtained powder was classified with a 35-mesh sieve to obtain an unvulcanized rubber powder having an average particle size of 220 μm, a hardness (Shore A) of 70 degrees after vulcanization, and a specific gravity of 1.2.

[0039]

[Table 1] Then, papermaking was performed as follows. First, using a beater, rockwool fibers (average fiber diameter 5 μm, average fiber length 7 mm) were disintegrated together with a large amount of water, and the fibers were uniformly dispersed in the water, and then pulped from fibrillated aromatic polyamide. Material was added and similarly dispersed. Then, the elastic powder and the dispersant were added to and dispersed in the same manner, and the obtained primary slurry was put into a pulper, and a latex binder was added to perform final disaggregation. Then, this slurry is put into a chest, water is added to adjust the concentration, and a flocculant is added to adjust the flocs to obtain a final slurry, which is then poured onto a wire of a Fourdrinier paper machine to obtain a wet paper web. Was formed, dehydrated and dried to produce a papermaking paper having a basis weight of 700 g / m ² .

The mixing ratio of the papermaking material is shown in Table 2 below.
As described above, two types of paper were prepared: a papermaking paper (1) having a relatively low elastic powder content and a papermaking paper (2) having a relatively high elastic powder content.

[0041]

[Table 2] The two types of papermaking papers (1) and (2) obtained as described above were stacked on the embodiment shown in FIG. 1, and the surface layer material (1
1) and (11) are overlaid, the temperature is 175 ° C., the time is 70 minutes,
By pressing at a pressure of 10 kg / cm ² , the unvulcanized rubber powder (EPDM) contained in the papermaking paper was vulcanized and, at the same time, the whole was laminated and integrated to obtain a cushioning pad for molding press of Sample No. 1. The surface layer material (11) used was one in which fluororubber was applied to both sides of glass cloth, and aromatic acrylic resin was applied to one side (release side) of the glass cloth.

Example 2 As a papermaking material, rockwool fiber, EPDM elastic powder produced by the kneading and pulverizing method, and a pulp-like substance and / or a binder were used as main components.

To produce the elastic powder, a rubber compound having the same composition as in Example 1 was used, and after kneading with a batch type internal mixer, the rubber compound 100 was used.
185 parts by weight of rockwool fiber (Asano CMF; manufactured by Nippon Cement Co., Ltd., average fiber diameter 5 μm, average fiber length 7 mm) as a grinding medium, and silicone oil (KF96-50CS as a liquid anti-adhesive agent) per part by weight. (Manufactured by Shin-Etsu Chemical Co., Ltd.) in an amount of 3.0 parts by weight, and kneaded and pulverized using a pressure kneader. Obtained rubber powder 100
In order to prevent powder re-adhesion, silica powder (Carplex 67; manufactured by Shionogi Pharmaceutical Co., Ltd.) as a solid anti-adhesive agent is added to a weight ratio of 6.2 parts by weight and mixed with a super mixer, Then, classification was carried out with a 60-mesh sieve to obtain an unvulcanized rubber powder having an average particle size of 75 μm, a hardness (Shore A) after vulcanization of 87 degrees, and a specific gravity of 1.8.

Then, a papermaking operation was carried out in the same manner as in the papermaking process of Example 1 with the mixing ratios of the papermaking materials shown in Table 3.
4 types of papermaking paper (3) with different formulations,
(4), (5) and (6) were produced. Papermaking paper (3)
The weight per unit area (6) was 700 g / m ² .

[0045]

[Table 3] And the various papermaking papers (3) to (6) obtained as described above
2-5, and the surface layer materials (11) and (11) are layered on both upper and lower surfaces and laminated and integrated by the same method as in Example 1, and the molding presses of Sample Nos. 2 to 5 are laminated. I got a cushion material.

Example 3 In this example, as the elastic powder, a rubber powder made of fluororubber finely divided by the method of kneading and pulverization was used.

As the rubber powder, the rubber compound having the compounding composition shown in Table 4 below was used.

[0048]

[Table 4] Using the above rubber compound, a pulverizing medium and a liquid anti-adhesive agent were added and blended in the proportions shown in Table 5 below, and kneaded and pulverized in the same manner as in Example 2, and a solid anti-adhesive agent was further added and mixed, followed by classification. Then, an unvulcanized rubber powder having an average particle size of 75 μm, a Shore A hardness after vulcanization of 92 degrees, and a specific gravity of 2.5 was produced.

[0049]

[Table 5] Then, in the mixing ratio of the papermaking material shown in Table 6, Example 1
A papermaking operation was performed in the same manner as in the papermaking process of No. 2, and two types of papermaking papers (7) and (8) having different formulations were produced.
The weight per unit area of papermaking papers (7) and (8) is 700 g.
/ M ² .

Example 4 This example consists of EDPM as elastic powder,
A rubber powder obtained by kneading and pulverizing hollow glass beads as a pulverizing medium is used.

The rubber powder was added to the compound as shown in Table 7 below.
The compounding composition of was used.

[0052]

[Table 7] Using the above rubber compound, a pulverizing medium and a liquid anti-adhesive agent were added and blended in the proportions shown in Table 8 below, and kneaded and pulverized in the same manner as in Example 2, and a solid anti-adhesive agent was further added and mixed, followed by classification. Then, an unvulcanized rubber powder having an average particle diameter of 75 μm, Shore A hardness after vulcanization of 85 degrees and a specific gravity of 1.2 was produced.

[0053]

[Table 8] Then, in the mixing ratio of the papermaking material shown in Table 9, Example 1
A papermaking operation was performed in the same manner as in the papermaking process of No. 2, and two types of papermaking papers (9) and (10) having different formulations were produced. The weight per unit area of the papermaking paper (9) was 700 g / m ² , and the weight per unit area of the papermaking paper (10) was 400 g / m ² .

[0054]

[Table 9] Then, the two types of papermaking paper (9) obtained above,
(10) was overlaid on the various aspects shown in FIG. 7, and the surface layer materials (11) and (11) were overlaid on both upper and lower surfaces and laminated and integrated by the same method as in Example 1, for the molding press of Sample No. 7. I got a cushion material.

(Comparative Example 1) 130 g of weight per unit area of spun yarn of aromatic polyamide fiber
/ M ² base fabric 4 layers, 2d (600% by weight) and 5d
An aromatic bar Tsu bets five layers having a basis weight 350 g / m ² consisting of polyamide fibers (40 wt%) are stacked alternately, the laminate consisting of Ba <br/> Tsu bets five layers, the base fabric 4 layers And these were integrated by needle punching. And 180
By applying a pressure of 20 kg / cm ² at 70 ° C. for 70 minutes, a non-woven fabric forming press cushion material having a basis weight of 2270 g / cm ² was obtained. This was designated as Sample No. 8.

Comparative Example 2 20 parts by volume of a pulp-like substance of a heat-resistant aromatic polymer (polymetaphenylene isophthalamide) adjusted to a drainage value of 200 seconds and an average fiber length of 150
80 μm fine rockwool fiber with a thickness of 4.1 μm
Volume parts were mixed to prepare an aqueous dispersion having a solid content concentration of 1%. This was made into wet paper with a cylinder paper machine, transferred to felt, and dehydrated to a water content of 80%. Further, 70 sheets of the wet paper thus obtained were laminated on a making drum, then squeezed by a hot press of 35 kg / cm ² and 140 ° C. and dried to have a basis weight of 2,800 g / m ² and a thickness of 2.4.
A board-shaped cushioning material for papermaking molding press having a size of mm was obtained. This was designated as Sample No. 9.

(Performance comparison test) Sample Nos. 1 to 7 produced in Examples 1 to 4 and samples obtained in Comparative Examples 1 and 2
With respect to the cushioning materials for forming presses of Nos. 8 and 9, the basis weight accuracy was measured, and a press test for examining durability was performed to examine changes in cushioning properties and thickness changes before and after the press test.

In the press test, a pressure cycle of 30 kg / cm ² and a heating temperature of 180 ° C. was maintained for 90 minutes, followed by cooling for 30 minutes while maintaining a pressurized state, and then depressurized release for 3 minutes. Went by.

Then, the above-mentioned areal accuracy, cushioning property, and thickness change were measured under the following conditions. The results are shown in Table 10 below.

Fabrication accuracy: Punching piece 12 in which a cushion material is punched at a pitch of 100 mm with a punch of 50 mm square.
Each one is weighed and the maximum weight W ₁ ,
Assuming that the minimum weight is W ₂ and the average weight is Wa, (W ₁ −
It was determined by the formula of W ₂ ) / Wa × 100.

Cushioning property: 8 kg / at a temperature of 120 ° C.
The amount of change in thickness when compressed to increase the pressure of cm ² to a pressure of 35 kg / cm ² was measured. The rate of change is 20
0 times press testing thickness change amount T ₁ of the post, when the thickness variation T ₂ of the previous press _{test, (T 1 -T 2) /} T 1 × 10
It was calculated as 0.

Thickness change: Pressure at room temperature, 35 kg / c
The thickness of the cushion material at the time of compression of m ² was measured. The rate of change was calculated according to the rate of change in the cushioning property.

[0063]

[Table 10] As shown in Table 10, the conventional non-woven cushion material of Comparative Example 1 (Sample No. 8) has a large variation in the areal accuracy and a good cushioning property in the initial stage. Reduce. In addition, the thickness is greatly reduced by repeated use, resulting in poor durability.

On the other hand, the conventional paper-made cushioning material of Comparative Example 2 (Sample No. 9) has a good basis weight accuracy and thickness change rate, but is inferior in cushioning property.

In contrast to these conventional products, the sample according to the present invention
The cushion materials of Nos. 1 to 7 are all excellent in unit weight accuracy and cushioning property, and the cushioning property is relatively well retained even after repeated use. Further, it can be seen that the change in thickness due to use is small and the durability is excellent.

[0066]

As is apparent from the above description, the cushioning material according to the present invention has a uniform thickness distribution, excellent basis weight accuracy, little change in thickness over time, and good cushioning properties. In addition, it has an excellent compressive and restoring force, and has an effect that the useful life can be remarkably increased.

Further, according to the method for producing a cushioning material of the present invention, uniformly finely divided elastic powder can be produced easily and at a high yield, and the elastic powder can be uniformly dispersed in the papermaking paper. Since it can be dispersed, it is possible to efficiently manufacture the cushioning material having the best characteristics described above.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a cushion material manufactured according to a first embodiment.

FIG. 2 is one of cushion materials manufactured by Example 2;
It is one block diagram.

FIG. 3 is another configuration diagram of the cushioning material manufactured according to the second embodiment.

FIG. 4 is still another configuration diagram of the cushioning material manufactured according to the second embodiment.

FIG. 5 is still another configuration diagram of the cushioning material manufactured according to the second embodiment.

FIG. 6 is a configuration diagram of a cushion material manufactured according to a third embodiment.

FIG. 7 is a configuration diagram of a cushion material manufactured according to a fourth embodiment.

[Explanation of symbols]

 1-10 ... Papermaking paper 11 ... Surface material

Claims (10)

(57) [Claims] 1. A and organic fibers and / or inorganic fibers, pressurized
An elastic body powder having a JIS A hardness of 20 to 98 degrees after vulcanization as a main component, and the elastic body powder is made of a papermaking paper uniformly dispersed and contained. Cushion material for molding press. 2. The cushion for a molding press according to claim 1, characterized in that, in addition to the organic fiber and / or the inorganic fiber and the elastic powder as a main component of the papermaking paper, a polymer pulp-like substance is further contained. Material. 3. The cushioning material for forming press according to claim 1, which further comprises a binder in addition to the organic fiber and / or the inorganic fiber, the elastic body powder, as a main component of the papermaking paper. 4. The main component of the papermaking paper, in addition to the organic fiber and / or the inorganic fiber, the elastic body powder, a polymer pulp-like substance and a binder are further contained. Cushion material for molding press. 5. The cushion material for a molding press according to claim 1, wherein a releasable surface layer material is stuck and integrated on both surfaces of the cushion material substrate. 6. The organic and inorganic fibers have a fiber diameter of 1 to 30 μm.
The cushioning material for molding press according to any one of claims 1 to 5, which has a fiber length of m and a fiber length of 300 to 15,000 µm. 7. The elastic powder has an average particle diameter of 20 to 250.
The cushioning material for forming press according to any one of claims 1 to 6, which has a thickness of μm. 8. Organic and / or inorganic fibers with high content
A body that combines the molecular pulp-like substance and elastic powder
The elastic powder content is set to 10-95% of the product
Molding according to any one of claims 1 to 8
Cushion material for press. 9. An elastic compound, powdered or fine
Add a fibrous solid grinding medium and knead and grind
An elastic body powder having a uniform particle diameter of 250 μm or less is produced, and the elastic body powder is mixed with at least organic fibers and / or
Dispersed in an aqueous slurry macerated paper making paper materials including aircraft fibers
Then, the elastic powder is uniformly dispersed inside the aqueous slurry.
Forming press paper characterized by forming a paper
Method for producing a ssion material. 10. An elastic compound for kneading and pulverization
40 to 400 parts by weight of the grinding medium is used for 100 parts by weight.
Cushion for molding press according to claim 10, which is mixed in a ratio.
Method of manufacturing wood materials.