JPH04300398A - Production of heat-resistant cushioning material - Google Patents

Abstract

PURPOSE:To produce the subject cushioning material excellent in strength and useful for molding, etc., by making a paper in the presence of a specified fine- grained polymer aggregate and a thermosetting binder under a specified condition, placing plural sheets of the resultant papers in layers while sandwiching sheet-shaped hot melt materials and subsequently pressing the layered material with heating. CONSTITUTION:With a filament such as aramide fiber, having 100mum-10mm average fiber length and 10-1000 aspect ratio and a fine-grained polymer aggregate having 300-900ml Canadian standard freeness, a thermosetting binder such as an epoxy resin is blended in an amount of 35-70vol.% on its pure polymer component base based on the total volume between the filament, the fine-grained polymer agregate and the thermosetting binder. From the resultant aqueous slurry, papers 3, 4, 6 and 7 are made while controlling the temperature during drying process within a range where the binder shows its reactivity so that the weight in a dried state may be 50-2000g/m<2>. Plural sheets of the obtained papers 3, 4, 6 and 7 are placed in layers followed by heat pressing for unification into one body, thus giving the objective cushioning material.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing heat-resistant cushioning materials used primarily in molding presses.

0002

[Prior Art] Conventionally, as a manufacturing method for a heat-resistant cushion material for molding, a fiber diameter of 0.5 without substantially containing shot was used.
~15μ, a fine inorganic fiber with a fiber length of 70 to 500μ,
Aqueous slurry mixed with pulp-like particles of a heat-resistant aromatic polymer with a drainage value of 150 seconds or more and less than 500 seconds was wet-formed to form wet paper, and the water content was adjusted to 50 to 95%. It is known that a desired number of sheets of wet paper are laminated and then dehydrated and dried under heat and pressure to integrate them (Japanese Patent Publication No. 2-6).
(See Publication No. 0799).

0003

[Problems to be Solved by the Invention] According to the above-mentioned conventional method for manufacturing heat-resistant cushioning materials, the Canadian standard freeness of the pulp particles is small and close to 0, so thick wet paper cannot be made in one go, and the basis weight is low at most. Since the limit is 30g/m2,
It is inefficient because it requires stacking a large number of wet papers, and since multiple papers are laminated only by intertwining them, the strength between the paper layers is low, so There are problems like this. That is, (a)
Warpage occurs. (b) Cracks occur. (c)
It expands when pressure is applied and contracts when heated. (d) Fine fibers scatter during use. (e) It has low bending strength and impact strength, and is easily chipped and damaged when it hits an object. (f) In addition to large settling, changes in temperature rise characteristics and cushioning properties are large, resulting in poor durability.

[0004] An object of the present invention is to provide a method for manufacturing a heat-resistant cushion material, which allows thick paper to be made as a material for the cushion material to be made in one step, and which has high strength between paper layers.

[0005]

[Means for Solving the Problems] In order to achieve the above object, the method for manufacturing a heat-resistant cushion material according to the present invention has the following features:
Long fibers with an average fiber length of 100 μm to 10 mm and an aspect ratio of 10 to 1000, and a Canadian standard freeness of 300.
The thermosetting binder was added to ~900 ml of the micronized polymer aggregate at a volume ratio of the pure polymer equivalent to the combined volume of the long fibers, the micronized polymer aggregate, and the thermosetting binder. The temperature in the drying process is kept within a range that can maintain the reactivity of the thermosetting binder, and the drying process is made to have a basis weight of 50 to 2000 g/m2. This method is characterized by making paper, stacking a plurality of sheets of paper, and then heating and pressurizing them to integrate the whole.

[0006] In this specification, the term "refined polymer aggregate" refers to a polymer raw material that is subjected to mechanical or chemical refining treatment to form a polymer fibrous aggregate, and in which all or part of it is It is fibrillated and branched into a spider web.

[0007] The fibers may be either inorganic fibers or organic fibers. Specific examples of inorganic fibers include rock wool fibers, alumina silicate fibers, alumina fibers, and wollastonite fibers. Specific examples of organic fibers include carbon fibers, polyphenylene sulfide fibers, phenolic fibers, and polyamide fibers. , polyarylate fibers, etc.

Specific examples of polymers include polyparaphenylene terephthalamide, polymethaphenylene terephthalamide, polyamide, polyacetal, polycarbonate,
Modified polyphenylene ether, polybutylene terephthalate, ultra-high molecular weight polyethylene, polysulfone, polyethersulfone, polyphenylene sulfide, polyarylate (U polymer), polyamideimide, polyetherimide, polyetheretherketone, polyimide, liquid crystal polymer, fluorine resin and modified resins thereof, as well as mixtures thereof.

Specific examples of thermosetting binders include epoxy resins, silicone resins, and phenol resins. The form may be granular, latex or emulsion. In the case of granular particles, the average particle size must be 0.0 to ensure uniform adhesion without uneven adhesion.
1 to 100 μm is preferable. If the diameter is 0.01 μm or less, the binder will flow out together with water during dehydration during papermaking. 1
If it exceeds 00 μm, the binder will precipitate and the yield will be poor. A particularly preferred range is 5 to 60 μm.

[0010] In the drying process during papermaking, the temperature range in which the reactivity of the thermosetting binder can be maintained varies depending on the type of binder used, but is generally 60 to 1
It is 00℃.

The number of stacked papers is preferably 2 to 4, and when heating and pressing the stacked papers, the heating temperature is 100 to 250°C and the pressure is 5 to 150 kg/cm 2 .

0012

[Function] The method for producing a heat-resistant cushion material according to the present invention uses long fibers with an average fiber length of 100 μm to 10 mm and an aspect ratio of 10 to 1000, and a Canadian standard freeness of 30.
Add a thermosetting binder to a micronized polymer aggregate of 0 to 900 ml so that the volume ratio in terms of pure polymer content is the combined volume of the long fibers, the micronized polymer aggregate, and the thermosetting binder. By using an aqueous slurry made by mixing 35 to 70% of the thermosetting binder, the temperature in the drying process is within a range that can maintain the reactivity of the thermosetting binder, and the basis weight when drying is 50 to 2000 g/m2. Since paper is made in this way, thick paper is
It can be made in two steps.

Furthermore, as mentioned above, the thermosetting binder has a volume ratio of 35 to 35 to the total volume of the long fibers, the micronized polymer aggregate, and the thermosetting binder in terms of pure polymer content. 70%, and the temperature during the drying process is within a range that can maintain the reactivity of the thermosetting binder, and after stacking multiple sheets of paper, heat and pressurize to integrate the whole. Since it is made of paper, the strength between the paper layers is high.

[0014] The average fiber length of the long fibers is 100 μm to 10 m.
m and the aspect ratio is 10 to 1000, so paper can be made that has high bending strength and impact strength and has a uniform basis weight. If the average fiber length is less than 100 μm or the aspect ratio is less than 10, the above-mentioned strength will not be sufficient, and if the average fiber length is 10 mm or the aspect ratio exceeds 1000, it will become pilled during the stirring process and the fixation of the binder will be poor, resulting in a decrease in the basis weight. Difficult to obtain uniform paper. A particularly preferable range is an average fiber length of 400 μm to 2 mm, and an aspect ratio of 100 to 400.
It is.

Since the Canadian standard freeness of the micronized polymer aggregate is 300 to 900 ml, thick adhesive paper in which fibers are entangled vertically and horizontally can be made in one step. If the volume is less than 300 ml, only thin paper will be obtained, and since it is necessary to stack a plurality of sheets, there will be no tangle in the vertical direction, and there is a risk of delamination between the layers. Moreover, if it exceeds 900 ml, the fixing rate of the binder will be extremely poor. A particularly preferred range is 500 to 700 ml.

[0016] The mixing ratio of the thermosetting binder is 3 to the total volume of the long fibers, the micronized polymer aggregate, and the thermosetting binder in terms of pure polymer content.
Since it is 5 to 70%, a satisfactory adhesive strength can be obtained. If it is less than 35%, the adhesive strength between stacked papers will be insufficient, and if it exceeds 70%, it will be uneconomical. A particularly preferred range is 40 to 50%.

[0017] The basis weight during drying during papermaking is 50~
Since it is set to 2000 g/m2, a strong adhesive paper with uniform binder particles dispersed without any uneven paper density can be obtained. If it is less than 50 g/m2, density unevenness of the paper becomes noticeable, binding of binder particles becomes uneven, and paper strength becomes weak. If it exceeds 2000 g/m2, it becomes too heavy and cracks occur when drying. A particularly preferred range is 500 to 1400 g/m2.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Examples of the present invention will be described below with reference to the drawings. Note that "parts" are based on weight.

Example 1 55 parts of alumina silicate fibers with an average fiber length of 600 μm and an aspect ratio of 143, and 10 parts of para-type aramid fibers subjected to micronization treatment (mechanical treatment) and adjusted to a Canadian standard freeness of 500 ml. To the mixture, 25 parts of granular epoxy resin with an average particle size of 50 μm and 10 parts of acrylic silica composite emulsion (solid content) were added.
The temperature in the drying process is lowered by using an aqueous slurry made by mixing alumina silicate fibers, para-aramid fibers, and binder (47.6% by volume in terms of pure polymer content). The temperature was set at 100° C., which is a temperature that can maintain the reactivity of the binder, and the paper was made to have a basis weight of 1000 g/m 2 upon drying, thereby obtaining paper with a thickness of 2.3 mm.

Then, as shown in FIG. 1, the thickness is 0 from the top.
．． 2mm paper-like para-aramid fiber (1), thickness 0.
1 mm first sheet-shaped heat-sealing material (2), the above paper (3)
(4), second sheet-shaped heat-sealing material with a thickness of 0.3 mm (5)
, the above papers (6) and (7), the first sheet-like heat-sealing material (8) with a thickness of 0.1 mm, and the paper-like para-aramid fiber (9) with a thickness of 0.2 mm were stacked, and then heated at 180°C. The whole was heated and pressurized at a surface pressure of 40 kg/cm2 for 70 minutes to integrate the whole, thereby obtaining a heat-resistant cushion material with a thickness of 4.0 mm.

[0021] In the above, the binder is a combination of granular epoxy resin and acrylic silica composite emulsion.

[0022] The first sheet-like heat-sealing materials (2) and (8) are sheet-like prepregs obtained by impregnating paper-like para-aramid fibers with epoxy resin and heating them; The fusing material (5) is a sheet prepreg obtained by impregnating a woven glass fiber cloth with an epoxy resin and heating and pressing the impregnated glass fiber cloth.

[0023] In this example, the paper-like para-aramid fibers (1) (9), the first sheet-like heat-sealing material (2) (8)
) and the second sheet-like heat-sealing material (5) with paper (3) (4)
Although (6) and (7) are listed above, these are not necessarily necessary.

Example 2 55 parts of rock wool fibers with an average fiber length of 400 μm and an aspect ratio of 143, and 10 parts of micronized (mechanically treated) para-aramid fibers whose Canadian standard freeness was adjusted to 500 ml. to the mixture,
25 parts of granular phenolic resin with an average particle size of 20 μm and S
10 parts solid content of BR latex (rock wool fiber,
From an aqueous slurry made by mixing para-aramid fibers and a binder (53.1% in terms of pure polymer volume volume ratio), the temperature in the drying process is controlled by the reactivity of the binder. The temperature is 100℃, which is the temperature that can maintain the
g/m2 to obtain paper with a thickness of 2.3 mm.

The following steps were carried out in the same manner as in Example 1 to obtain a heat-resistant cushion material with a thickness of 4.0 mm.

[0026] In the above, the binder is a combination of granular phenolic resin and SBR latex.

Example 3 A mixture of 65 parts of rock wool fibers with an average fiber length of 400 μm and an aspect ratio of 143 and 5 parts of micronized (mechanically treated) para-aramid fibers whose Canadian standard freeness was adjusted to 500 ml was prepared. , 20 parts of granular epoxy resin with an average particle size of 50 μm and 10 parts of acrylic silica composite emulsion in solid content (based on the combined volume of rock wool fiber, para-aramid fiber, and binder, the pure polymer content of the binder) From an aqueous slurry made by mixing 43.3% (converted volume ratio),
The temperature in the drying process was set at 100°C, which is a temperature that can maintain the reactivity of the binder, and the basis weight was 1.
000g/m2, thickness 2.3mm
got the paper.

The following steps were carried out in the same manner as in Example 1 to obtain a heat-resistant cushion material with a thickness of 4.0 mm.

[0029] In the above, the binder is a combination of epoxy resin and acrylic silica composite emulsion.

Comparative Example: 90 parts of rock wool fibers with an average fiber length of 150 μm and an aspect ratio of 30, refined treatment (chemical treatment) with Canadian standard freeness adjusted to 5 ml.
A paper was made from an aqueous slurry prepared by mixing 10 parts of previously used meta-aramid fibers to a dry basis weight of 1000 g/m2, but the drainage was poor and paper could not be obtained.

[0031]

Effects of the Invention: According to the method for producing a heat-resistant cushion material of the present invention, the thick paper used as the material for the cushion material can be made in one step, resulting in high production efficiency and a heat-resistant material with high strength between the paper layers. Since a cushioning material is obtained, all of the above-mentioned drawbacks caused by the low strength between paper layers can be overcome.

[Brief explanation of the drawing]

FIG. 1 is a vertical cross-sectional view of a heat-resistant cushion material produced by the method of the present invention.

[Explanation of symbols]

(1) (9) Paper-like para-type aramid fiber (2) (
8) First sheet-shaped heat-sealing material (3) (4) (6)
(7) Paper

Claims (1)

[Claims] Claim 1: A thermosetting binder is added to a finely treated polymer aggregate having long fibers with an average fiber length of 100 μm to 10 mm and an aspect ratio of 10 to 1000 and a Canadian standard freeness of 300 to 900 ml, and a thermosetting binder is added to the pure polymer. From an aqueous slurry made by mixing long fibers, micronized polymer aggregates, and thermosetting binder at a volume ratio of 35 to 70% based on the combined volume, the temperature during the drying process is be within the range that can maintain the reactivity of the thermosetting binder, and have a basis weight of 50 to 2000 when drying.
A method for producing a heat-resistant cushion material, which comprises making paper so as to give a weight ratio of 1.3 g/m2, stacking a plurality of sheets of paper, and then heating and pressing them to integrate the whole.