JP5280771B2 - Permeable mold-forming composition for pulp mold - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a permeable mold forming composition for pulp molds wherein weight is light, processability is excellent, the formation of mold surfaces of various shapes by cutting operation is easy and opening holes for the purpose of permeability by drilling is not necessary, and furthermore, to provide pulp molds formed by filling a pulping solution into the inner part of a permeable mold and permeating water out of the mold. <P>SOLUTION: A permeable mold forming composition for pulp molds comprising (A) particles having an average particle size of 1.4 to 32.0 mm which contains synthetic resin and (B) a binder is prepared. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a water-permeable mold-forming composition for pulp mold.

Conventionally, as a mold for a pulp mold, a plurality of through holes for removing water in a papermaking liquid are opened with a drill in a metal mold that imparts a desired shape of the pulp mold. A paper net for preventing paper leakage has been used at the mouth (see, for example, Patent Document 1).
Japanese Patent Application Laid-Open No. 5-057738

  However, in this method, there are problems in terms of cost and productivity, such as the metal mold is expensive and heavy, and a long time is required for drilling or wire netting work. It was. Further, since the required change in the shape of the pulp mold is extremely frequent, it has been eagerly desired for the mold to be able to respond quickly to such needs.

  The inventor of the present invention has arrived at the present invention as a result of intensive studies to solve the above problems. That is, this invention is a water-permeable type forming composition for pulp molds containing the resin containing particle | grains (A) with an average particle diameter of 1.4-32.0 mm, and a binder (B).

The water-permeable mold-forming composition for pulp mold of the present invention has the following effects.
(1) A water-permeable mold for pulp mold having excellent water permeability is provided.
(2) The water-permeable mold can be easily provided with mold surfaces of various shapes by cutting.
(3) The water-permeable type does not need to be opened with a drill or the like, and since it is finely porous, there is no need to attach a paper net for preventing paper leakage.
(4) The water-permeable mold is lighter and more productive than a metal mold.

[Synthetic resin-containing particles (A)]
(A) in the present invention is a particle containing the synthetic resin (a1). (A1) includes a thermoplastic resin and a thermosetting resin.
Examples of the thermoplastic resin include vinyl resin [polyolefin resin [eg, polypropylene, polyethylene, polyvinyl chloride, ethylene-vinyl acetate copolymer resin (EVA), ethylene-ethyl acrylate copolymer resin, etc.], polyacrylic resin [eg, polymethacrylic resin]. Acid methyl etc.], polystyrene resin [vinyl group-containing aromatic hydrocarbon alone or vinyl group-containing aromatic hydrocarbon, and at least one selected from the group consisting of (meth) acrylic acid esters, (meth) acrylonitrile and butadiene) Copolymers as structural units, such as polystyrene, styrene / acrylonitrile copolymer (AN resin), acrylonitrile / butadiene / styrene copolymer (ABS resin), methyl methacrylate / butadiene / styrene copolymer (MBS resin), styrene/ Polyester resin [eg, polyethylene terephthalate, polybutylene terephthalate, polycyclohexanedimethylene terephthalate, polybutylene adipate, polyethylene adipate, etc.]; Polyamide resin [eg, nylon 66, nylon 69, etc.] Nylon 612, Nylon 6, Nylon 11, Nylon 12, Nylon 46, Nylon 6/66, Nylon 6/12, etc.]; Polycarbonate resin [eg, polycarbonate, polycarbonate / ABS resin alloy, etc.]; Polyacetal resin, fluororesin, thermoplastic Examples thereof include polyurethane resins and mixtures of two or more thereof.

  Examples of the thermosetting resin include polyurethane resin, epoxy resin, phenol resin, silicone resin, unsaturated polyester resin, melamine resin, urea resin, and polyimide resin.

Among these (a1), the thermosetting resin is preferable from the viewpoint of the adhesiveness with the binder (B), the ease of cutting, and the durability of the water-permeable mold for pulp mold, and more preferably Polyurethane resin (thermosetting), epoxy resin.
(A1) may be non-hollow or hollow (such as a microballoon). Examples of the microballoon include Matsumoto Microsphere F-80SDE and MFL series [both manufactured by Matsumoto Yushi Seiyaku Co., Ltd.], phenolic microballoon BJO-0930 [manufactured by Union Carbide Co., Ltd.], Scotchlite K-15, Examples include plastic microballoons such as K-37 [both manufactured by Scotchlite Co., Ltd.].

(A) may contain inorganic powder (a2) in addition to the synthetic resin (a1).
(a2) includes calcium carbonate, talc, metal (iron, aluminum, zinc, copper, etc.) powder, metal oxide (alumina, zinc oxide, copper oxide, magnesium oxide, titanium oxide, etc.) powder, metal hydroxide ( Aluminum hydroxide etc.) powder, ceramic (silicon nitride, zirconia etc.) powder, silicon dioxide, bentonite, mica, milled fiber and the like.
Of these (a2), calcium carbonate, talc, bentonite and mica are preferred from the viewpoint of ease of cutting, and calcium carbonate and talc are more preferred.

  The weight ratio of (a1) and (a2) is preferably 60/40 to 98/2, more preferably 75/25 to 95/5, from the viewpoint of lightness of the water permeability type for pulp mold and ease of cutting. It is.

In (A), in addition to the synthetic resin (a1) and the inorganic powder (a2), bubbles (a3) and / or inorganic microballoons (a4) may be contained for the purpose of further weight reduction.
As (a3), when the synthetic resin (A1) is a thermosetting polyurethane resin, carbon dioxide gas obtained by water foaming or foaming agent (trichloromonofluoromethane, dichlorodifluoromethane, pentane, etc.) that is usually performed, Examples include halogenated alkane gas and alkane gas bubbles.
Moreover, it can also be set as the bubble which consists of arbitrary gas (air, nitrogen, argon, etc.) by the mechanical froth method.
When the synthetic resin (A1) is a thermoplastic resin, it is possible to obtain desired particles by crushing the obtained molded product by containing bubbles by injection molding while dispersing the foaming agent.

  Examples of the inorganic microballoon (a4) include hollow fine particles made of an inorganic material (glass, alumina, shirasu, carbon, etc.).

The density of (A) is preferably from 0.05 to 1.45 g / cm ³ , more preferably from 0.1 to 1.5 from the viewpoints of mechanical strength and lightness of the water permeability type for pulp mold and ease of cutting. 3 g / cm ³ .

  The particle shape of (A) is not particularly limited, and may be any shape such as a spherical shape, an elliptical spherical shape, a dice shape, a plate shape, and an indefinite shape. Among these, the indefinite shape, the spherical shape, and the elliptical shape are preferable from the viewpoint that the particles adhere to each other and a water channel in the water-permeable type can be secured.

Examples of the method for producing (A) include a method of crushing a molded product by injection molding, extrusion molding, mold casting, or the like with a crusher.
As the crusher, a uniaxial crusher, a biaxial crusher, and a hammer type crusher that are usually used for recycling plastics and wood can be used. Further, in order to facilitate crushing and to finely pulverize, the molded product may be frozen and then pulverized. By sieving the crushed and pulverized particles using a sieve, particles having a desired average particle diameter can be obtained.

The average particle diameter of (A) is 1.4 to 32.0 mm, preferably 3.4 to 22.8 mm, and more preferably 7.1 to 14.3 mm. If the average particle size is less than 1.4 mm, the water permeability is poor, and if it exceeds 32.0 mm, the irregularities on the inner surface of the mold increase, and a pulp mold having excellent surface smoothness cannot be obtained.
The average particle diameter of (A) is determined by the opening size of the sieve for sieving the particles. The sieve conforms to JIS A 1204-2000 “Soil Particle Size Test Method”, and the opening size in the present invention is 0.85 mm, 2.0 mm, 4.75 mm, 9.5 mm, 19 mm, 26. 5mm and 37.5mm are included.
In the case of an intermediate value of particles that can pass through each sieve, for example, “4.75 mm sieve”, particles of 2.0 to 4.75 mm can pass, so the average particle diameter is (2.0 + 4.75) / 2 = 3.4 mm.
When the sieve products having different openings are mixed, calculation is made from the weight distribution of the sieve articles having different openings. For example, in the case of a mixture of 30% by weight of 26.5 mm sieve product and 70% by weight of 9.5 mm sieve product, the average particle size is (22.8 × 0.3 + 7.1 × 0.7) = 11.8 mm. It becomes. Here, 22.8 mm is obtained from (19 + 26.5) /2=22.8 mm, and 7.1 mm is obtained from (4.75 + 9.5) /2=7.1 mm.

[Binder (B)]
The binder (B) includes a reaction curable resin-forming composition.
Examples of the composition include resin compositions such as poly (meth) acrylate, polyurethane, polyepoxy, and cyanoacrylate, and any resin composition that is usually used as an adhesive can be used.

  Of these, poly (meth) acrylate resins, polyurethane resins, and polyepoxy resins are preferred from the viewpoint of workability because they do not require heating / drying, have excellent adhesive strength, and workability.

[Water-permeable type forming composition for pulp mold]
The water-permeable mold-forming composition for pulp mold of the present invention comprises the above synthetic resin-containing particles (A) and a binder (B).
The weight ratio of (A) and (B) is preferably 60/40 to 90/10, and more preferably 70/30 to the viewpoint of securing a water passage and (B) uniformly reaching the surface of (A). 85/15.

The composition is produced, for example, by mixing (A) and (B) using a mixer (such as a mortar mixer or a hard mixer) having a structure in which a stirring blade is in a container and the stirring blade or the container rotates. can do.
Among the mixing conditions, the temperature and pressure are preferably normal temperature and normal pressure, and the mixing speed is preferably 20 to 60 rpm. Furthermore, it can be also produced by putting (A) and (B) in a shallow container or bucket for mortar and mixing them with a shovel, a scoop or a hand mixer.

[Water-permeable type for pulp mold]
The manufacturing method of the water-permeable type for pulp mold of the present invention includes the following two methods.
(1) A rectangular parallelepiped or a cylindrical block is manufactured and cut to produce a water-permeable mold.
(2) Fill a molding die having a cavity with a desired shape of the water-permeable mold, and remove the mold to produce a water-permeable mold.
(1) is a rectangular parallelepiped or cylindrical block obtained by filling a mold having a rectangular parallelepiped or cylindrical cavity with the mixture of (A) and (B), reaction curing, and demolding. This is a method for producing a water-permeable mold by cutting.
(2) is a method for producing a water-permeable mold by filling a cavity having the shape of a water-permeable mold with the mixture of (A) and (B), and curing and releasing in the same manner as (1). .
Both methods require a step of curing the mixture of (A) and (B).
The curing temperature is usually 5 to 45 ° C., preferably 10 to 35 ° C. from the viewpoint of productivity, and the curing time is usually 0.5 to 6 hours, preferably 1 to 4 hours from the viewpoint of quality stability and productivity. is there.
The water permeability of the water-permeable type for pulp mold of the present invention is preferably a flow rate when only water is passed through the water-permeable type at normal temperature and pressure from the viewpoint of papermaking workability and smoothness of the surface of the obtained pulp mold. 0.5 to 10 cm / second, more preferably 1 to 5 cm / second.

In the method (1), the water-permeable mold for pulp mold of the present invention is obtained by cutting the surface of the cured product into a desired shape.
Cutting can be done by hand machining using a chisel or canna, but usually an NC machining program is created from a CAD drawing and machine cutting is performed using an NC milling machine or machining center.
The number of rotations of the cutter during the cutting is preferably 300 to 10,000 rpm, more preferably 1,000 from the viewpoint of workability and cutting resistance of the cured product when the blade diameter is 20 mm and the maximum cutting depth is 10 mm. ~ 5,000 rpm.
The moving speed of the blade during cutting is preferably 100 to 8,000 mm / min, more preferably 500 to 8000 mm from the viewpoint of workability and cutting resistance of the cured product when the blade diameter is 20 mm and the maximum cutting depth is 10 mm. 5,000 mm / min.

[Pulp mold]
The pulp mold of the present invention can be produced by filling a papermaking liquid into a cavity of the water-permeable mold for pulp mold and allowing water to permeate out of the mold. Examples of the method for allowing the water in the papermaking liquid to permeate out of the mold include a method for allowing water to naturally permeate at normal pressure and a method for forcibly permeating water by reducing the pressure outside the mold.
Examples of the pulp used for the papermaking liquid for pulp mold include used paper such as newspapers, magazines and cardboard, or a mixture of the used paper and pure pulp. The weight ratio of the used paper and pure pulp is recycled paper, economical and From the viewpoint of mechanical properties of the pulp mold, it is preferably 50/50 to 100/0. The papermaking liquid for pulp mold is obtained as a solution obtained by stirring the pulp in water to loosen the fibers, or as a solution obtained by adding a sulfuric acid band, a sizing agent or the like to the solution.

  Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited thereto. In the following, “part” means “part by weight” and “%” means “% by weight”.

The composition, symbols, etc. of the raw materials used in the examples and comparative examples are as follows.
Synthetic resin-containing particles (A-1): Polyurethane resin-containing block material [trade name "Sanmodul
No. 7K-1505 ", manufactured by Sanyo Chemical Industries, Ltd., density 0.64 g
/ Cm ³ . same as below. ] Towa Kogyo Co., Ltd. hammer type small universal crush
[Product name “HM-4060”, manufactured by Towa Industries Co., Ltd., and so on. ]
After pulverization at 1,200 rpm for 5 minutes,
Sieve with a 2.0 mm sieve, average grain remaining on the 0.85 mm sieve
Particles with a diameter of 1.4 mm. The sieve here and below is JIS A 12
A sieve based on 04-2000 “Soil Particle Size Test Method” was used.
Synthetic resin-containing particles (A-2): The polyurethane resin-containing block material is powdered in the same manner as (A-1).
The particles obtained by pulverization are sieved with a sieve having a mesh opening of 37.5 mm.
. Particles with an average particle size of 32.0 mm remaining on a 5 mm sieve.
Synthetic resin-containing particles (ratio A-1): A polyurethane resin-containing block material as in (A-1)
The particles obtained by pulverization are sieved with a sieve having an aperture of 0.85 mm.
. Particles with an average particle size of 0.6 mm remaining on a 425 mm sieve.
Synthetic resin-containing particles (ratio A-2): Polyurethane resin-containing block material as in (A-1)
The particles obtained by pulverization were sieved with a sieve having an opening of 53.0 mm, and particles having an average particle diameter of 45.3 mm remained on the sieve having an opening of 37.5 mm.
Synthetic resin-containing particles (A-3): rigid urethane foam [trade name “foam light board F
L-50 ", manufactured by Inoac Co., Ltd., density 0.05 g / cm ³ ] (A
The particles obtained by pulverization in the same manner as in -1) are sieved with a sieve having an opening of 4.75 mm.
Particles having an average particle diameter of 3.4 mm remaining on a sieve having a sieve and an opening of 2.0 mm.
Synthetic resin-containing particles (A-4): Polyurethane resin-containing block material [trade name "Sanmodul
"Le TH-6504", manufactured by Sanyo Chemical Industries, Ltd., density 1.45 g / cm
³ ] is pulverized in the same manner as in (A-1), and the particle size is 4.75 m.
The average particle size of 3.4 mm remaining on the sieve having a mesh size of 2.0 mm
Particles.
Synthetic resin-containing particles (A-5): Epoxy resin-containing block material [trade name "Sun Module J
T-5 ”, Sanyo Chemical Industries, Ltd., density 0.79 g / cm ³ ] (A
The particles obtained by pulverization in the same manner as in -1) are sieved with a sieve having an opening of 4.75 mm.
Particles having an average particle size of 3.4 mm remaining on a sieve having an aperture of 2.0 mm.
Binder (B): Epoxy resin two-component curable resin composition (adhesive) [trade name “Sanmodul
AD-201 ", manufactured by Sanyo Chemical Industries Co., Ltd.]
Pulp mold paper making solution: Stir 1 blanket paper (about 10g) and 2L of tap water
Blender [Brand name “Blender HBH450”, manufactured by Hamilton Corporation]
The solution was stirred and mixed at 24,000 rpm for 5 minutes.

Examples 1-7
The synthetic resin-containing particles and the binder (B) were put in a 20 L open pail can with the mixing ratio shown in Table 1, and stirred and mixed for 10 minutes using a hard mixer MK-2 manufactured by Nippon Sosei Kogyo Co., Ltd. The mixture was filled in a mold having inner dimensions of 20 cm in length, 20 cm in width, and 5 cm in depth, the surface was leveled with a mortar trowel, and allowed to stand at 25 ° C. for 4 hours, and the cured product was demolded. The cured product was processed under the following cutting conditions using an NC machine, and a hollow having an inner dimension of 15 cm in length, 15 cm in width, and 3 cm in depth was carved to obtain a water-permeable type for pulp mold. The following items were evaluated about the water-permeable type for pulp molds obtained. The results are shown in Tables 1 and 2.
<Cutting conditions>
NC machine: Model MM800, manufactured by Iwama Kogyo Co., Ltd. Blade: 20 mm diameter high-speed flat end mill, manufactured by OSG Co., Ltd. Feed rate: 500 mm / min Number of revolutions: 3,000 rpm
Cutting depth: 30mm
Step amount: 10 mm

<Permeable evaluation items for pulp mold>
(1) Cutting property Cutting sound at the time of cutting, scattering of synthetic resin-containing particles, and the appearance of the finished mold were evaluated according to the following criteria.
○ Low cutting sound, no particle scattering, good mold appearance △ Low cutting sound, particle scattering, slightly poor mold appearance × High cutting sound, particle scattering, poor mold appearance (2) Water permeability The papermaking liquid was poured into a water-permeable mold for pulp mold (vertical 15 cm × width 15 cm × depth 3 cm) that was left in a horizontal position so that the liquid did not break and the liquid did not overflow. The time from the start of pouring until the water apparently disappeared from the surface was measured and used as the water permeation time. From the water permeation time, the water permeation rate (cm / sec) was determined by the following formula.

Permeability rate (cm / sec) = 2000 / (15 × 15 × permeability time (sec))

(3) Paper Leakage Property After the water permeation in (2) above, the paper fiber and water paste remaining on the mold surface was allowed to stand in a dryer at 60 ° C. for 6 hours together with the water permeable mold. Thereafter, the water-permeable mold was taken out of the dryer and the pulp mold was removed. The weight of the pulp mold was measured, and the papermaking loss rate (%) was calculated from the weight of the newspaper used for preparing the papermaking liquid by the following formula.

Papermaking loss rate (%) = (newspaper weight used−pulp mold weight) × 100
/ (Weight of newspaper used)

(4) Pulp mold surface appearance The surface of the demolded pulp mold in contact with the water-permeable mold surface was observed and evaluated according to the following criteria.

○ There is almost no flaking of paper fibers and the surface is smooth.

Comparative Examples 1-2
A pulp mold water-permeable mold was prepared and evaluated in the same manner as in the Examples at the blending ratio shown in Table 1. The results are shown in Table 1.

  The water-permeable mold-forming composition for pulp mold of the present invention provides a water-permeable mold for pulp mold having excellent water permeability. The water-permeable mold is lightweight and excellent in productivity, and it is easy to give mold surfaces of various shapes by cutting, so egg trays, fruit trays, bottling case interior materials, electrical and industrial products, etc. Suitable as a material for water-permeable molds for producing pulp molds used in various shapes for a wide range of applications such as cushioning materials or fixing materials, corner pads, food containers, school teaching materials, folk crafts, disposable products for hospitals and special needs homes, etc. It can be used and is extremely useful.

Claims (6)

A water-permeable mold-forming composition for pulp mold, comprising synthetic resin-containing particles (A) having an average particle size of 1.4 to 32.0 mm and a binder (B). The composition according to claim 1, wherein the density of (A) is 0.05 to 1.45 g / cm ³ . The composition according to claim 1 or 2, wherein the weight ratio of (A) to (B) is 60/40 to 90/10. The water-permeable type | mold for pulp molds which shape | molds the composition in any one of Claims 1-3. A pulp mold formed by filling the mold according to claim 4 with a papermaking liquid and allowing water to pass outside the mold. A method for producing a pulp mold comprising filling a papermaking liquid into a mold according to claim 4 and allowing water to permeate out of the mold.