JP2002307431A - Granular molding compound and molded object - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a granular molding compound showing reutilization properties as resources and easy treatment properties in treatment after use and excellent not only in moldability but also in the stability of cushioning capacity with the elapse of time, and a molded object. SOLUTION: A granular molding compound is prepared by entirely or partially applying a thermoplastic resin layer to the surface of granular matter, which consists of pulp, hollow fine particles and a binder component, and used to obtain the molded object. The hollow fine particles are dispersed in the intertices of pulp fibers and has function for forming the lightweight granular matter. By compounding the hollow fine particles, the molding compound excellent in lightweight properties and cushioning properties can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention uses a granular molding material obtained by forming a granular material from pulp, hollow fine particles, and a binder, and providing a thermoplastic resin layer on the surface of the granular material. Accordingly, the present invention relates to a molding material technical field which aims to provide a molded article having excellent recyclability and easy processing properties and excellent buffering properties.

[0002]

2. Description of the Related Art In a precision device such as an electric product or an optical device, a cushioning material is used for the purpose of protecting the product from damage and damage due to vibration and impact applied during transportation. Styrofoam molded articles have been generally used as these cushioning materials from the past. In recent years, as other cushioning materials, laminating paper cardboard,
A pulp slurry composed of water and pulp fibers was adhered to a mold formed according to the shape of the object to be protected and a mold manufactured according to the shape of the object to be protected, and then dried and released. A pulp molded article, a vacuum-pressed air molded article formed by heating a thermoplastic resin sheet, and then molding it into a desired mold shape by air or vacuum are also used. However, in recent years, interest in environmental issues has increased,
Easy disposal, incineration, and recyclability when products are discarded are becoming inevitable factors in designing products. Styrofoam, which has been used for a long time, has excellent cushioning properties and heat insulation properties, and has relatively good formability. Problems arise. When incinerating styrene foam, the amount of heat generated during combustion is
It is higher than paper and polyester resin, and there is a concern that the incinerator may be damaged. When the landfill is performed, there is a problem that styrene foam remains without being decomposed in the soil. As alternatives, products such as pulp molded products, corrugated products, and vacuum / pressure molded products are commercially available.
However, these products do not have sufficient buffering capacity, and are inferior in moldability to an arbitrary shape as compared with Styrofoam. Specifically, in a pulp molded product, since a low-density and thick molded product cannot be obtained, the shape that can be manufactured when obtaining a cushioning material function is limited. That is, since the material of the pulp mold itself has a small buffering property and the buffering property is obtained by using the bending of the molded product, its use is limited to protection of relatively lightweight equipment, eggs and the like. Since corrugated products are manufactured by lamination, bending, combination, and the like in a planar shape, there are great restrictions on the shape, and it is difficult to form a shape that matches the shape of the object to be protected. In vacuum-pressure molded products, the thermoplastic resin sheet is heated and molded into a shape that matches the mold surface, so the protrusions and the like are likely to be thin, and the height and shape of the molded product are limited. There is. In addition, as in the case of the pulp molded product, the cushioning property is obtained by using the bending of the sheet molded product, so that the use thereof is limited to the protection of relatively lightweight equipment and components. Various means have been proposed to solve these problems. For example,
As a means for improving the buffering property of the pulp mold base material, a method of manufacturing a pulp mold by adding a binder or hollow particles to pulp as a main component (JP-A-6-10300)
No.), a method of kneading waste paper pulp, modified starch, moisture, and hollow particles, placing the mixture in a mold, and heating to obtain a molded article having excellent buffer performance (JP-A-9-78500). (Japanese Patent Application Laid-Open No. HEI 6-15753) has been proposed in which a molded product is obtained using pulp beads obtained by holding a foaming agent or bubbles generated by foaming.

[0003]

However, in these methods, it is not easy to increase the thickness of the base material itself. Although it is excellent, the raw material itself has poor fluidity and it is difficult to uniformly fill the mold, so depending on the molded shape, it may take time or use a large amount of solvent such as water during production. There are problems that it takes time for drying and that the held bubbles are not always stable with time, and that the buffer performance may be affected with time. In view of these problems, intensive research has been conducted using pulp excellent in recyclability and ease of processing as a raw material, and as a result, it has good moldability and good granularity with good temporal stability of buffer performance. The material was obtained and completed the present invention. The present invention, in order to solve the above-mentioned problems, in the treatment after use, while providing recyclability, easy processing, excellent moldability, excellent molding material with excellent stability of buffer performance over time, and It is intended to provide a molded article.

[0004]

According to the present invention, there is provided a granular material comprising a pulp, hollow fine particles and a binder component, wherein the granular material comprises a thermoplastic resin layer provided entirely or partially on the surface thereof. A molded body is obtained by using a molding material. The hollow fine particles are dispersed between the pulp fibers and have a function of forming light-weight granules. The binder functions to maintain the shape of the particulate matter including the hollow fine particles. By blending the hollow fine particles, it is possible to obtain a molding material that is lightweight and has excellent cushioning properties.

[0005] The invention according to claim 2 is the invention wherein the hollow fine particles are heat-expandable microcapsules. The heat-expandable microcapsules are particularly capable of obtaining hollow fine particles having a low specific gravity, and can provide a granular molding material having excellent lightness and cushioning properties. According to a third aspect of the present invention, there is provided the granular molding material according to the first or second aspect, wherein the pulp contains recycled pulp or finely-crushed waste paper. The invention according to claim 4 is the granular molding material according to claim 1 or 2, wherein the plasticizing temperature of the thermoplastic resin layer is lower than the heat resistant temperature of the hollow fine particles. The invention according to claim 5 is characterized in that the binder is soluble in a solvent or is derived from a dispersion or emulsion of the solvent. It is a molding material.

The invention according to claim 6 is the invention according to claims 1 to 5
Wherein the granular molding materials according to any of the above are combined with each other to form an aggregate. In the invention according to claim 7, the molded product has an apparent specific gravity of 0.05.
成形 0.25. The molded article according to claim 6, wherein The invention according to claim 8 is the molded article according to claim 6 or 7, wherein a coating layer is provided on the entire surface or partially on the surface of the molded article.

Hereinafter, the present invention will be described in detail. As the pulp containing the recycled pulp constituting the granular molding material of the present invention, kraft pulp using softwood or hardwood, soda pulp, groundwood pulp, sulfite pulp, thermomechanical pulp, etc., used paper, old corrugated paper, old magazines Regenerated pulp, flocculent crushed material, finely crushed material, etc. derived from the above can be used alone or in combination of two or more.

As the hollow fine particles, phenol balloons and those obtained by heating thermally expandable microcapsules to obtain hollow fine particles can be used. In the heat-expandable microcapsules, the outer shell thermoplastic resin covers the inner shell solvent, and the outer shell thermoplastic resin is softened by heating, and the inner shell solvent is gasified and the volume expands. However, since hollow particles of low specific gravity can be obtained,
It is suitable for a granular molding material excellent in cushioning property and lightness. Specifically, as a component of the inner shell of the heat-expandable microcapsules, solvents such as isobutane, pentane, isopentane, hexane, isooctane, and petroleum ether are exemplified.
Examples of the outer shell component include a thermoplastic resin copolymerized from two or more monomers such as vinylidene chloride, acrylonitrile, methacrylonitrile, acrylate, and methacrylate.The outer shell wraps the inner shell component. Heat-expandable microcapsules can be preferably used.
By dispersing the hollow fine particles between the fibers of the pulp, the hollow fine particles have a function of forming a light-weight and highly-buffered granular material.
In using such a heat-expandable microcapsule in the production of the granular molding material of the present invention, one obtained by previously expanding to form hollow fine particles may be mixed with pulp, and after mixing with pulp, expand to form hollow fine particles. Is also good. Of course, a composite containing hollow fine particles as a component may be used. For example, composite hollow fine particles in which inorganic powder is coated on the surface of hollow fine particles whose outer shell is a thermoplastic resin can be used. Examples of the inorganic powder include calcium carbonate, talc, silica, and titanium oxide.

The binder is not particularly limited as long as it binds the fibers containing the hollow fine particles, and may be a polymer soluble in a solvent, an emulsion liquid, or a fine particle dispersion. Those obtained are preferably used. Examples of the solvent include, but are not limited to, water, alcohols such as methanol, ethanol, propanol and isopropanol, and esters such as ethyl acetate. Examples of binders include:
Water-soluble polymers include cellulose derivatives such as carboxymethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, methylcellulose, hydroxypropylmethylcellulose, polyacrylamide derivatives, esterified starch, starch derivatives such as etherified starch, and polyvinyl alcohol. , Polyvinylpyrrolidone, casein, chitosan, sodium alginate, and the like, but are not limited thereto.

As a method for producing a granular material, a granular material can be produced by a stirring and mixing granulation method, an extrusion granulation method, a tumbling granulation method, a fluidized bed granulation method, and the like, but is not limited thereto. Not something. As the size of the granular material, those having an average size of 2 mm to 20 mm can be used, but 3 mm to 10 mm.
mm is more preferably used. The size of the granules may be the same or a mixture of different sizes. The shape of the granular material is not particularly limited as long as it is a small lump, but a granular material such as a sphere, an ellipsoid, a column, a flat sphere, a flat ellipsoid, and an approximate shape thereof can be preferably used. Even if it is a small lump having an undetermined mass, it can be used as long as it can be filled in a mold. If the average size is smaller than 2 mm, the fluidity tends to be insufficient, and a problem is likely to occur in the filling property of the mold. Those having an average size larger than 20 mm are disadvantageous when the molding shape is complicated.

The resin formed on the surface of the granular material is not particularly limited as long as it has thermoplasticity.
It is preferable to use a resin having a plasticization temperature lower than the heat resistance temperature of the hollow fine particles. Examples of thermoplastic resins include polyolefin resins such as polypropylene and polyethylene, polyamide resins, polyester resins, polyvinyl acetate resins, ethylene-vinyl acetate copolymer resins, ethylene-acrylic acid copolymer resins containing cross-linked metal salts, and metal salts. Examples thereof include an ethylene-methacrylic acid copolymer resin containing a crosslinked product, but are not particularly limited thereto. The above thermoplastic resins can be used alone or in combination of two or more.

As a method of forming a thermoplastic resin layer on the surface of the granular material, a method of spraying or spraying a powder, an emulsified dispersion or a solution of the above-mentioned thermoplastic resin or the like can be mentioned. The amount of the thermoplastic resin layer formed on the surface of the granular material is preferably 1% to 40% by weight relative to the granular material, but is preferably 2% to 20% in terms of buffering property. More preferred. When the amount of the resin used is less than 1%, the strength as a molded article cannot be sufficient, and when it is more than 40%, there is a problem in recyclability and easy processing after use.

[0013] As a method of obtaining a compact formed by assembling the granular molding materials with each other, a molding die is filled with the material,
Examples include a method of compressing to a predetermined density and heating, but are not limited thereto. For heating, a method of providing a ventilation hole in the mold and blowing hot air, a method of heating the inside of the mold with high frequency, a method of heating the entire mold, and the like can be mentioned.

The apparent specific gravity of the above-mentioned molded article may be changed appropriately according to the required buffering performance, and the apparent specific gravity is preferably 0.05 to 0.25 from the viewpoint of moldability. The apparent specific gravity of the molded article is set at 0.08 in terms of buffering property.
More preferably, it is set to 0.2. When the apparent specific gravity of the molded article is less than 0.05, the strength of the molded article is insufficient, and when the apparent specific gravity is more than 0.25, sufficient cushioning property cannot be obtained. The content of the hollow fine particles is preferably 5% by volume to 50% by volume with respect to the apparent volume of the above-mentioned molded product. A suitable molded body can be obtained. A molded product having a particularly preferable content of 15% by volume to 40% by volume is used. In this case, the content of the hollow fine particles is 5
If the content is less than 50% by volume, a sufficient improvement in the buffering property cannot be obtained, and if the content is more than 50% by volume, the bonding strength of the pulp fiber is reduced, and the strength as a molded product is insufficient. When the content of the hollow fine particles in the molded body is increased, the volume occupied by the pulp is relatively reduced, and the apparent specific gravity of the molded body can be reduced. When the apparent specific gravity of the molded article is increased, the content of the hollow fine particles in the molded article is decreased. As the hollow fine particles, those having a true specific gravity of 0.2 to 0.005 can be used, and those having a true specific gravity of 0.1 to 0.01 can be more preferably used. The apparent specific gravity of the compact and the content of the hollow fine particles may be appropriately combined in accordance with the buffer performance required by the compact.

By forming a coating layer on the surface of the molded article, the components of the molded article can be prevented from falling off, and a more suitable cushioning material can be obtained. The coating layer formed on the surface of the molded article is not particularly limited as long as the coating layer is also deformed or bent according to the deformation of the molded article subjected to the load. A method of attaching to a surface, a method of spraying or spraying a polymer solution or an emulsion liquid dissolved in a solvent such as water on a molded body and drying to form a coating layer, and forming the molded body in the polymer solution or the emulsion liquid. After immersion, a method of forming a coating layer by drying. The coating layer may be formed on the entire surface of the molded body, or may be formed partially.
Examples of the polymer include an acrylic copolymer-based coating, a vinyl acetate-based coating, a polyolefin-based coating, a polysaccharide-based coating, a basic polysaccharide-based coating, and the like, but are not limited thereto. Not something.

[0016]

The present invention will be described below with reference to experimental examples. Example 1 Pulp: Recycled pulp derived from waste paper 100 parts by weight Hollow fine particles: 3 parts by weight of thermally expandable microcapsule foamed material Binder: 1 part by weight aqueous solution of polyvinyl alcohol 150 parts by weight Among the above raw materials, Matsumoto Yushi Pharmaceutical of hollow fine particles ( Manufactured by Matsumoto Microsphere F-80ED has a true specific gravity of 0.02, a particle size distribution of 30 to 150 μm, and an average particle size of 90 μm.
m and a heat-resistant temperature of 120 ° C. were used. The above raw materials are sufficiently crushed and mixed by a crushing mixer ("Proshare mixer" manufactured by Taiyo Kiko Co., Ltd.) until the whole becomes wet. The mixed raw material was processed by a tumbling granulator to obtain a granular material. The size of the obtained granules was small lumps having a distribution of about 3 mm to 8 mm. After drying the granules, 15 parts by weight of a thermoplastic resin dispersion: vinyl acetate-polyolefin copolymer resin (trade name “Chemipearl V-100”, 40% solid content, manufactured by Mitsui Chemicals, Inc.) is sprayed on the granules. , 5
After drying at 0 ° C., a granular molding material was obtained. The obtained granular molding material was charged into a mold, and heated by passing hot air of about 100 ° C. through the mold. After cooling the inside of the mold, a molded body (apparent specific gravity 0.12) in which the granular materials were mutually bonded was obtained. The ratio of the hollow fine particles in the molded product was 18% by volume. Using the granular molding material obtained in the same way, width 15 cm
Molded product having a depth of 15 cm and a thickness of 5 cm (apparent specific gravity 0.1
2) were fabricated three times.

The molded article was subjected to a load drop test using an impact load test apparatus in accordance with JIS Z0235. First, one of the compacts was allowed to stand at 20 ° C. (humidity: 65%) for 24 hours.
When dropped from 0 cm, the maximum impact acceleration under load was 62G. (1G is converted to 9.8 m / s ² ) To investigate the effect of high temperature and high humidity, another molded body was left at 40 ° C. (80% humidity) for 24 hours and weighed. When a 5.8 kg load was dropped from a height of 60 cm, the maximum impact acceleration received was 6
It was 3G. In order to examine the stability over time, the remaining one compact was left at 20 ° C. (65% humidity) for one month, and a load of 5.8 kg was dropped from a height of 60 cm. The maximum impact acceleration was 63G. Almost the same stable results were obtained in the load drop test.

Examples 2 to 8 and Comparative Examples 1 to 4 In Example 1, the amount of the hollow fine particles was varied to prepare a granular molding material, and the width was 15 cm, the depth was 15 cm, and the thickness was 5 cm.
cm of a compact was obtained. After leaving each of these compacts at 20 ° C. (65% humidity) for 24 hours, a load of 5.8 kg was dropped from a height of 60 cm, and the maximum impact acceleration under the load is shown in Table 1.

[0019]

[Table 1]

Comparative Example 5 A drop test was performed using expanded polystyrene. Expanded polystyrene molded article (width 15c) produced by bead foaming method
m depth 15cm thickness 5cm; apparent specific gravity 0.017)
Was left at 20 ° C. (65% humidity) for 24 hours, and then a 5.8 kg load was dropped from a height of 60 cm. As a result, the maximum impact acceleration under load was 66 G. The other molded body was allowed to stand at 40 ° C. (80% humidity) for 24 hours, and then a 5.8 kg load was dropped from a height of 60 cm.
G and no change was observed. Example 1 above
8 and Comparative Example 5, in the load drop test under the above conditions, a result was obtained in which the molded article made of the granular molding material of the present invention had the same buffering property as expanded polystyrene.

Example 9 Pulp: 100 parts by weight of recycled pulp derived from waste paper Hollow fine particles: 3 parts by weight of a thermally expandable microcapsule foam (trade name "Matsumoto Microsphere F-80ED" manufactured by Matsumoto Yushi Seiyaku Co., Ltd.) Agent: 140% by weight of a 1% by weight aqueous solution of carboxymethyl cellulose The above-mentioned raw material was treated in the same manner as in the above (Example 1),
Granules were obtained. After drying the granular material, a thermoplastic resin emulsified dispersion: a crosslinked product of an ethylene-methacrylic acid-based copolymer resin metal salt (trade name “Chemipearl S-100” solid content 2)
After spraying 20 parts by weight (7%, manufactured by Mitsui Chemicals, Inc.) on the granular material, it was dried at 50 ° C. to obtain a granular molding material. The obtained granular molding material was charged into a mold, and heated by passing hot air of about 100 ° C. through the mold. After cooling the inside of the mold, a compact (apparent specific gravity 0.14) in which the granular materials were bonded to each other was obtained. Using the granular molding material obtained in the same way, width 15 cm
Molded product having a depth of 15 cm and a thickness of 5 cm (apparent specific gravity 0.1
4) was produced. After leaving the molded body at 20 ° C. (65% humidity) for 24 hours, a load of 5.8 kg was applied to a height of 6 mm.
When dropped from 0 cm, the maximum impact acceleration under load was 65G.

Example 10 Pulp: 100 parts by weight of finely-milled newspaper waste Hollow microparticles: 4 parts by weight of thermally expandable microcapsule foam (trade name "Matsumoto Microsphere F-80ED" manufactured by Matsumoto Yushi Seiyaku Co., Ltd.) Binder: Hydroxypropyl methylcellulose 0.8% by weight aqueous solution 120 parts by weight Finely pulverized newspaper waste paper used was finely pulverized into a floc with a hammer mill or the like. The above raw material was treated in the same manner as in the above (Example 1) to obtain a granular material. After drying the granules, a thermoplastic resin: polyester resin fine powder (trade name “Aronmelt PES-085P”, manufactured by Toa Gosei)
After spraying 20 parts by weight of a 30% by weight aqueous dispersion onto a granular material, the resultant was dried at 50 ° C. to obtain a granular molding material. The obtained granular molding material was charged into a mold, and heated by passing hot air of about 100 ° C. through the mold. After cooling the inside of the mold, a compact (apparent specific gravity 0.10) in which the granular materials were mutually bonded was obtained. Using the granular molding material obtained in the same way, width 15 cm
Molded product having a depth of 15 cm and a thickness of 5 cm (apparent specific gravity 0.1
0) was prepared. At 20 ° C (65% humidity)
%) For 24 hours, and then a 5.8 kg load was dropped from a height of 60 cm. The maximum impact acceleration under the load was 60 G.

Example 11 Pulp: 100 parts by weight of finely-milled newspaper waste Hollow particles: 20 parts by weight of composite hollow particles (trade name "Matsumoto Microsphere MFL-100CA" manufactured by Matsumoto Yushi Pharmaceutical Co., Ltd.) Binder: hydroxy 140% by weight of a 1.0% by weight aqueous solution of propylmethylcellulose As the finely pulverized newspaper paper, finely pulverized into a floc with a hammer mill or the like was used. The above raw material was treated in the same manner as in the above (Example 1) to obtain a granular material. After drying the granules, a thermoplastic resin: polyester resin fine powder (trade name “Aronmelt PES-085P”, manufactured by Toa Gosei)
After spraying 20 parts by weight of a 35% by weight aqueous dispersion onto a granular material, the resultant was dried at 50 ° C. to obtain a granular molding material. The obtained granular molding material was charged into a molding die, and heated by passing hot air at about 100 ° C. into the molding die. After cooling the inside of the mold, a compact (apparent specific gravity 0.15) in which the granular materials were bonded to each other was obtained. Using the granular molding material obtained in the same way, width 15 cm
Molded product with a depth of 15 cm and a thickness of 5 cm (apparent specific gravity 0.1
5) was produced. 20 ° C (65% humidity)
%) For 24 hours, and when a load of 5.8 kg was dropped from a height of 60 cm, the maximum impact acceleration under the load was 67G.

Example 12 A 15 cm width, 1 depth, separately prepared in the above “Example 10”
A 5 cm thick 5 cm thick molded body (apparent specific gravity 0.10) was coated on a vinyl acetate coating agent ("Polysol SH-5" manufactured by Showa Polymer Co., Ltd.).
02 ") was applied by a dipping method and dried to form a coating layer. (Coating amount 15 g / m ² ) After leaving this molded body at 20 ° C. (humidity 65%) for 24 hours, a load of 5.8 kg was dropped from a height of 60 cm. Impact acceleration is 58
G. (Example 13) An acrylic copolymer-based coating agent ("Movinyl 9001" made by Clariant Polymer) was applied to a molded product (apparent specific gravity 0.10) having a width of 15 cm, a depth of 15 cm, and a thickness of 5 cm separately produced in the above "Example 10".
Was applied by a dipping method and dried to form a coating layer.
(Coating amount: 12 g / m ² ) After leaving the molded body at 20 ° C. (humidity: 65%) for 24 hours, a load of 5.8 kg was dropped from a height of 60 cm, and the maximum load was received. Impact acceleration is 61
G.

[0025]

According to the granular molding material obtained by the present invention, by using pulp as a raw material, a molded article excellent in recyclability and easy processing can be produced.
In addition, by blending the hollow fine particles into the pulp raw material, it is possible to produce a molded article that is lightweight and has excellent buffer performance.

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) C08K 7/22 C08L 1/02 C08L 1/02 B29K 1:00 // B29K 1:00 105: 04 105: 04 B29C 67 / 22 F-term (reference) 4F070 DA02 DB03 DC02 DC05 4F074 AA02 AA02L AA42 AE07 CA52 CB62 CB68 CC04X CC04Y CC05Z CC10X CC12Y CE01 DA02 DA08 4F201 AA01 AA19 AE07 AG20 BA02 BA03 BC01 BC02 BC19 BC25 BL42 AU07 UE27 UN08 4J002 AB01W AB03Y AB04Y AB05Y AD02Y BD10X BE02Y BG04X BG05X BG10X BG13Y BJ00Y CC03X EG026 FA10X

Claims (8)

[Claims] 1. A granular molding material characterized in that a thermoplastic resin layer is provided on the whole or part of the surface of a granular material comprising pulp, hollow fine particles and a binder. 2. The granular molding material according to claim 1, wherein the hollow fine particles are heat-expandable microcapsules. 3. The granular molding material according to claim 1, wherein the pulp contains recycled pulp or finely crushed waste paper. 4. The thermoplastic resin layer according to claim 1, wherein the plasticizing temperature is lower than the heat-resistant temperature of said hollow fine particles.
Or the granular molding material according to 2. 5. The granular molding material according to claim 1, wherein the binder is soluble in a solvent, or derived from a dispersion or an emulsion of the solvent. 6. A molded article characterized in that the granular molding materials according to claim 1 are combined with each other to form an aggregate. 7. The molded article according to claim 6, wherein the molded article has an apparent specific gravity of 0.05 to 0.25. 8. The molded article according to claim 6, wherein a coating layer is provided on the entire surface or partially on the surface of the molded article.