JP7087660B2 - Foam - Google Patents

Description

The present invention relates to a foam containing cellulose fibers and polypropylene.

The foam has excellent cushioning and heat insulating properties against physical impact, and is therefore used in various applications such as cushioning materials, packaging materials, heat insulating materials, and soundproofing materials. As a foam, a composition containing cellulose fibers and polypropylene is known to be foamed using water as a foaming agent.

For example, Patent Document 1 describes a foam obtained by supplying a paper component, a thermoplastic resin, and water to an extruder, heating and kneading the paper component in the extruder, and foaming with the vapor pressure of water. In Patent Document 1, a crushed material having a side length of about 3 mm to 5 mm obtained by crushing used paper with a crusher is used as a paper component, and a powdery polypropylene homopolymer is used as a thermoplastic resin to produce a density of 0. A foam of .085 g / cm ³ (85 kg / m ³ ) is described.

Japanese Unexamined Patent Publication No. 2000-273800

In order to improve the cushioning property and heat insulating property of the foam against physical impact, it is effective to increase the pore amount of the foam, that is, to reduce the density of the foam. However, the conventional foam containing cellulose fibers and polypropylene has a problem that it is difficult to reduce the density of the foam.

The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to provide a foam containing cellulose fibers and polypropylene and having a low density.

In order to solve the above problems, the present inventor has focused on the hydrophilicity of cellulose fibers and repeated diligent studies. As a result, a composition containing a hydrophilic cellulose fiber having a contact angle with water of less than 30 degrees, a hydrophobic cellulose fiber having a contact angle with water of 30 degrees or more, and polypropylene in a predetermined ratio was used with water. The present invention has been completed by finding that it is possible to obtain a foam having a low density by foaming.
That is, the present invention adopts the following configuration.

[1] A hydrophilic cellulose fiber having a contact angle with water of 10 degrees or less , a hydrophobic cellulose fiber having a contact angle with water of 50 degrees or more, and polypropylene are contained, and the content of the hydrophilic cellulose fiber is 10. The content of the hydrophobic cellulose fiber is in the range of 2% by mass or more and 50% by mass or less, and the content of the polypropylene is 38% by mass or more and 88% by mass or less in the range of mass% or more and 60% by mass or less. A foam characterized by being within the following range.

[2] The foam according to the above [1], wherein the hydrophobic cellulose fiber is a cellulose fiber whose surface is treated with a hydrophobic agent.

[3] The foam according to the above [1], wherein the hydrophobic cellulose fiber is a cellulose acetate fiber having a vinegarization degree of 30% or more and 63% or less.

[4] The foam according to any one of the above [1] to [3], wherein the hydrophilic cellulose fiber is made by defibrating used paper.

[5] The foam according to any one of the above [1] to [4], wherein the density is 50 kg / m ³ or less.

According to the present invention, it is possible to provide a foam containing cellulose fibers and polypropylene and having a low density.

Hereinafter, embodiments of the foam of the present invention will be described.

<Foam>
The foam of the present embodiment comprises hydrophilic cellulose fibers having a contact angle with water of less than 30 degrees, hydrophobic cellulose fibers having a contact angle with water of 30 degrees or more, and polypropylene. The foam of the present embodiment is produced by using water as a foaming agent. The foam is a porous body having a skeleton composed of a composition containing hydrophilic cellulose fibers, hydrophobic cellulose fibers, and polypropylene, and pores formed between the skeletons. The contact angle of the cellulose fiber with water is a value measured by the following method.

"Measuring method of contact angle of cellulose fiber"
50 mg of the cellulose fiber of the sample and 50 ml of distilled water are stirred using a homogenizer, and the obtained suspension is filtered through a membrane filter having a diameter of 25 mm to obtain a cellulose fiber sheet. The obtained cellulose fiber sheet was dried at room temperature, set in a vacuum press device, vacuum degassed at 150 ° C. under atmospheric pressure for 1 minute, and then vacuum pressed at the same temperature at a press pressure of 10 MPa for 4 minutes. I do. Next, the cellulose fiber sheet after vacuum pressing is further pressed at room temperature, atmospheric pressure, and a pressing pressure of 10 MPa for 5 minutes to prepare a sheet for measuring the contact angle. Pure water is dropped on the obtained contact angle measuring sheet, and the contact angle of water droplets on the sheet surface is measured. The contact angle is measured at three points on one contact angle measuring sheet, and the average of the measured values at these three points is taken as the contact angle of the sample. When the pure water dropped on the contact angle measuring sheet permeates the contact angle measuring sheet and there are no water droplets on the sheet surface, the contact angle is set to 0 degrees.

(Hydrophilic cellulose fiber)
The hydrophilic cellulose fiber has an action of retaining water, which is a foaming agent, when producing a foam. In the foam of the present embodiment, the water retained in the hydrophilic cellulose fibers evaporates to foam and form pores. The contact angle of the hydrophilic cellulose fiber with water is less than 30 degrees, preferably 20 degrees or less, and particularly preferably 10 degrees or less.

The content of the hydrophilic cellulose fiber of the foam is in the range of 10% by mass or more and 60% by mass or less. If the content of the hydrophilic cellulose fiber is too small, the amount of water retained during the production of the foam is too small, the amount of foam is reduced, and the density of the foam may be increased. On the other hand, if the content of the hydrophilic cellulose fiber is too large, the content of other components is relatively small, so that it becomes difficult to foam during the production of the foam, and the density of the foam may increase. The content of the hydrophilic cellulose fiber of the foam is preferably in the range of 10% by mass or more and 55% by mass or less.

As the material of the hydrophilic cellulose fiber, one or more pulps selected from wood-based fibers such as coniferous and broad-leaved trees, non-wooden fibers, ginseng fibers, and bacterial-derived fibers are used as raw materials. For example, mechanical pulp (MP; mechanical pulp, GP; crushed wood pulp, RGP; refiner ground pulp, TMP; thermomechanical pulp, CTMP; chemithermomechanical pulp, etc.) and chemical pulp (KP; kraft pulp, SP; sulfate pulp). , AP; alkaline pulp, etc.), recycled pulp (recycled paper such as used paper and scraps, cardboard) can be used. Examples of conifers used as raw materials for pulp include red pine, black pine, spruce, larch, larch, radiata pine, long leaf pine, short leaf pine, slush pine, loblory pine, white spruce, black spruce, fir, douglas fur, etc. Examples include balsam fur, spruce, and pine. Examples of hardwoods include beech, oak, oak, eucalyptus, poplar and the like. Examples of non-wooden fibers include linters, cotton, rice straw, straw, Abra palm empty fruit bunch (EFB), bamboo, sugar cane bagasse, hemp, cannabis, Manila hemp, flax, reeds and the like. Examples of gin skin fibers include mulberry and mitsumata. Examples of bacterial-derived fibers include bacterial cellulose and the like.

As the hydrophilic cellulose fiber, it is preferable to use a defibrated and / or crushed paper, and it is particularly preferable to use a defibrated waste paper. The method for defibrating the paper is not particularly limited, and for example, a crusher such as a millstone grinder, a beating machine, or a shredder can be used. Examples of the crusher include a stone mill type crusher manufactured by Masuko Sangyo Co., Ltd. (trade name: Mascoroider), a beating machine manufactured by Aikawa Iron Works Co., Ltd. (trade name: RF single refiner), and a hand shredder manufactured by Sanwa Supply Co., Ltd. (trade name: Mascoroider). Product name: PSD-12) and the like.

The average particle size of the hydrophilic cellulose fiber measured by the following method is preferably in the range of 10 μm or more and 5 mm or less, and more preferably in the range of 20 μm or more and 3 mm or less. When the average particle size of the hydrophilic cellulose fiber is 10 μm or more, less energy is required for crushing, so that the burden on the environment is small and the manufacturing cost is low, which is preferable. When the average particle size of the hydrophilic cellulose fibers is 5 mm or less, high-magnification foaming is possible and a low-density foam can be obtained, which is preferable.

"Measuring method of average particle size of cellulose fibers"
The average particle size of the cellulose fibers used as the material of the foam in the present embodiment means that the average particle size is a value measured by the method shown below.

A dispersion liquid is prepared by dispersing the cellulose fibers of the sample in ion-exchanged water as a dispersion medium. As a pretreatment, the dispersion is irradiated with ultrasonic waves for 30 minutes. Then, the dispersion is placed in a cell of the following particle size distribution measuring device, irradiated with ultrasonic waves for 1 minute, and then the average particle size is measured under the following measurement conditions. In addition, the dispersion medium is placed in the cell of the particle size distribution measuring device, and the particle size is measured as a blank.
The average particle size is measured a plurality of times for one dispersion, and the average of the obtained measured values is taken as the average particle size of the sample.

Particle size distribution measuring device; Laser diffraction / scattering type particle size distribution measuring device (manufactured by HORIBA, Ltd., trade name: LA-950V2)
Measurement conditions; Measurement unit: Wet
Measurement mode: Manual flow cell measurement
Particle size standard: Volume standard
Refractive index: 1.50-0.00i (sample refractive index) /1.33-0.00i (dispersion medium refractive index)

(Hydrophobic cellulose fiber)
Hydrophobic cellulose fiber has a thick skeleton by uniformly dispersing water so that water, which is a foaming agent, does not partially accumulate when producing a foam, and uniformly promoting foaming due to evaporation of water. It has the effect of producing a foam having constant pores and uniform communication holes. Foams with single pores (independent pores) are prone to shrinkage when water completely evaporates and the temperature of the foam drops, whereas foams with homogeneous communication pores evaporate water completely. Even if the temperature of the foam is lowered, shrinkage is unlikely to occur. Therefore, the foam of the present embodiment has a low density and high shape stability. The contact angle of the hydrophobic cellulose fiber with water is 30 degrees or more, preferably 50 degrees or more and 150 degrees or less.

The content of the hydrophobic cellulose fiber of the foam is in the range of 2% by mass or more and 50% by mass or less. If the content of the hydrophobic cellulose fiber is too small, the foaming due to evaporation of water during the production of the foam becomes non-uniform, the foam tends to shrink, and the density of the foam may increase. On the other hand, if the content of the hydrophobic cellulose fiber is too large, the amount of water retained during the production of the foam is too small, the amount of foam is reduced, and the density of the foam may be increased. The content of the hydrophobic cellulose fiber of the foam is preferably in the range of 3% by mass or more and 30% by mass or less.

As the hydrophobic cellulose fiber, one obtained by treating the surface of the cellulose fiber with a hydrophobic agent can be used. As the cellulose fiber before being treated with the hydrophobizing agent, hydrophilic cellulose fiber can be used. As the hydrophobic agent, a hydrophobic compound covalently bonded to cellulose and a compound having an affinity for cellulose can be used. The compound covalently bonded to cellulose is preferably a compound having a reactive group and a hydrophobic group covalently bonded to cellulose. Examples of the reactive group include a (meth) acryloyl group, a carboxyl group, a trialkoxysilyl group, a dialkoxysilyl group and the like. Examples of the hydrophobic group include an alkyl group having 1 to 12 carbon atoms and an alkenyl group having 1 to 12 carbon atoms. The hydrogen of the alkyl group and the alkenyl group may be substituted with a halogen element such as fluorine. As the compound covalently bonded to cellulose, alkyl (meth) acrylate, alkyl ketene dimer, and alkenyl succinic anhydride can be used. Compounds having an affinity for cellulose include various metal soaps (metal soap stearate; for example, aluminum stearate, barium stearate, calcium stearate, lithium stearate, zinc stearate, magnesium stearate, sodium stearate, etc. , Or 12-hydroxystearic acid soap, bechenic acid soap, montanic acid soap, lauric acid soap, all of which may be metal salts such as calcium, magnesium, zinc, aluminum, barium, lithium, sodium potassium) and various alkyls. Ammonium salts, animal-derived wax (honey wax, whale wax, cellac wax, etc.), plant-derived wax (carnauba wax, wood wax, rice bran wax, candelilla wax), petroleum-derived wax (paraffin wax, microcrystallin wax), mineral-derived wax ( Montan wax, ozokelite), rosin, rosin soap can be used.

Further, as the hydrophobic cellulose fiber, a fiber made of a cellulose derivative obtained by hydrophobicizing cellulose can be used. Examples of the cellulose derivative include methyl cellulose and cellulose acetate. The degree of vinegarization of cellulose acetate is preferably in the range of 30% or more and 63% or less.

The hydrophobic cellulose fiber is preferably a cellulose fiber whose surface is treated with a hydrophobic agent, particularly an alkyl (meth) acrylate, or a cellulose acetate fiber having a vinegarization degree of 30% or more and 63% or less.

The average particle size of the hydrophobic cellulose fiber is preferably in the range of 10 μm or more and 5 mm or less, and more preferably in the range of 20 μm or more and 3 mm or less, like the above-mentioned hydrophilic cellulose fiber.

(polypropylene)
As the polypropylene, for example, it is preferable to use polypropylene having an MFR (melt flow rate, temperature: 230 ° C., load: 2.16 kg) in the range of 0.1 g / 10 minutes or more and 100 g / 10 minutes or less. One type of polypropylene may be used alone, or two or more types of polypropylene having different characteristics such as MFR may be used in combination. For example, low MFR polypropylene having an MFR (temperature: 230 ° C., load: 2.16 kg) in the range of 0.1 g / 10 minutes or more and 20 g / 10 minutes or less, and MFR (temperature:) higher than the low MFR polypropylene. Two types of polypropylene having a high MFR (230 ° C., load: 2.16 kg) may be used in combination. By using two or more kinds of polypropylenes having different characteristics in combination, the density and thermal conductivity of the foam can be adjusted to be in a desired range.

The polypropylene content of the foam is in the range of 38% by mass or more and 88% by mass or less. If the polypropylene content is too low, the mechanical strength of the foam may decrease. On the other hand, if the polypropylene content is too high, the foam tends to shrink during the production of the foam, and the density of the foam may increase. The polypropylene content of the foam is preferably in the range of 40% by mass or more and 80% by mass or less. That is, the total content of the hydrophilic cellulose fiber and the hydrophobic cellulose fiber of the foam is preferably in the range of 20% by mass or more and 60% by mass or less.

The shape of polypropylene used as a material is preferably pellet or powder. Pellet-shaped polypropylene has typographical properties such as spherical, hemispherical, almond-shaped, columnar, prismatic, plate-shaped, and flake-shaped. The powdered polypropylene is obtained by crushing the above pelletized polypropylene into a powder. The powdery polypropylene preferably has a particle size of 2 mm or less.

(Density of foam)
If the density of the foam is too high, the pore amount of the foam becomes relatively small, and the cushioning property against physical impact and the heat insulating property may be lowered. Therefore, the density of the foam is preferably 50 kg / m ³ or less, and more preferably 45 kg / m ³ or less. On the other hand, if the density of the foam is too low, the strength of the foam may decrease. Therefore, the density of the foam is preferably 10 kg / m ³ or more, and more preferably 15 kg / m ³ or more.

(Shape of foam)
The shape of the foam of the present embodiment is usually a shape in which a plurality of granular foam particles are connected in a string shape (bead shape) or a strand shape. The granular foam particles constituting the beaded foam are preferably spherical. However, the granular foam particles do not have to be true spheres, and may be elliptical spheres or may have irregularities on the surface. The foam of the present embodiment can be cut into various sizes, processed and used. For example, in the case of a beaded foam, it may be divided into individual granular foam particles and used. Further, in the case of a strand-shaped foam, it may be cut and used as granular granular foam particles, or a plurality of strand-shaped foams may be fused and integrated in a bundled state. You may let me use it.

<Manufacturing method of foam>
Next, a method for producing the foam of the present embodiment will be described.
The foam of the present embodiment is, for example, a step of kneading hydrophilic cellulose fibers, hydrophobic cellulose fibers and polypropylene to form a first kneaded product (first kneaded product forming step), and a first kneaded product. It includes a step of kneading with water to produce a second kneaded product (second kneaded product forming step) and a step of evaporating the water content of the second kneaded product to form a foam (foam product forming step). It can be manufactured by the method. The first kneaded product has a hydrophilic cellulose fiber content of 10% by mass or more and 60% by mass or less, and a hydrophobic cellulose fiber content of 2% by mass or more and 50% by mass or less. , The content of polypropylene is in the range of 38% by mass or more and 88% by mass or less.

(1st kneaded product forming step)
As a kneading device for kneading the hydrophilic cellulose fiber, the hydrophobic cellulose fiber and the polypropylene in the first kneaded product forming step, a continuous kneader or a batch type kneader can be used. Examples of the continuous kneader include a single-screw kneader and a twin-screw kneader. Examples of batch type kneaders include Banbury mixers and pressurized kneaders.

Since the densities of the cellulose fibers and polypropylene to be kneaded in the first kneaded product forming step are significantly different, it is preferable to mix the cellulose fibers and polypropylene in advance to form a mixture before putting them into the kneading apparatus. By putting it into a kneading apparatus as a mixture of cellulose fibers and polypropylene, a first kneaded product having a uniform composition can be obtained in a short time.

(Second kneaded product generation step)
In the second kneaded product forming step, it is preferable to use a continuous kneader as a kneading device for kneading the first kneaded product and water. Examples of the continuous kneader include a single-screw kneader and a twin-screw kneader. The continuous kneader preferably has a water introduction means for introducing water in the middle of the cylinder.

The kneading conditions such as the temperature of the cylinder part and the temperature of the die part of the continuous kneader, the screw rotation speed, and the water supply speed to the continuous kneader are the contents, materials and shapes of cellulose fibers and polypropylene, and the purpose. It can be appropriately determined according to the density range of the foam and the like.
Specifically, the temperature of the cylinder portion and the temperature of the die portion of the continuous kneader are preferably in the range of 160 ° C. or higher and 190 ° C. or lower. When the temperature of the cylinder portion and the temperature of the die portion are within the above ranges, foaming of the second kneaded product is promoted. The screw rotation speed is preferably in the range of 50 rpm or more and 400 rpm or less. The speed of water supply to the continuous kneader is preferably such that the water content of the second kneaded product produced by kneading the first kneaded product and water is 10% by mass or more and 40% by mass or less.

The first kneaded product forming step and the second kneaded product forming step may be continuously performed. For example, a continuous kneader is used as a kneading device, and hydrophilic cellulose fibers, hydrophobic cellulose fibers, and polypropylene are put into the continuous kneader to generate a first kneaded product, and then water is added to the continuous kneader. It may be supplied and the first kneaded product and water may be kneaded to produce a second kneaded product. By continuously performing the first kneaded product forming step and the second kneaded product forming step in this way, a second kneaded product having a uniform composition can be obtained in a relatively short time.

(Foam form generation process)
In the foam formation step, the moisture of the second kneaded product extruded from the die portion of the continuous kneader is evaporated to generate a foam. The evaporation of the water content of the second kneaded product can be carried out in the atmosphere. Normally, it is extruded from the die portion of the continuous kneader and the water content of the second kneaded product evaporates to form a foam. The generated foam may be cut to a length suitable for the intended use.

The foam of the present embodiment having the above-mentioned structure has a hydrophilic cellulose fiber content of 10% by mass or more and 60% by mass or less, and a hydrophobic cellulose fiber content of 2% by mass. Since it is in the range of 50% by mass or less and the content of polypropylene is in the range of 38% by mass or more and 88% by mass or less, foaming due to evaporation of water proceeds uniformly during the production of the foam. It is easy, the thickness of the skeleton is constant, and a uniform communication hole is easily formed. Therefore, the foam of the present embodiment has a low density and high shape stability.

Further, in the foam of the present embodiment, the hydrophobic cellulose fiber is a cellulose fiber whose surface is treated with a hydrophobic agent, particularly an alkyl (meth) acrylate, or the degree of vinegarization is within the range of 30% or more and 63% or less. In the case of certain cellulose acetate fibers, it is possible to more reliably form uniform communication holes, and it is possible to more reliably reduce the density of the foam.

Further, in the foam of the present embodiment, when the hydrophilic cellulose fiber is made by defibrating used paper, effective use of resources can be achieved.

Further, in the foam of the present embodiment, when the density is as low as 50 kg / m ³ or less, the amount of pores is large, so that it can be advantageously used as a cushioning material, a packaging material, a heat insulating material, and a soundproofing material.

Although the embodiments of the present invention have been described above, the present invention is not limited to this, and can be appropriately changed without departing from the technical idea of the invention.

Hereinafter, the action and effect of the present invention will be described with reference to Examples. In this example, the contact angle of the cellulose fiber with water was measured by the above method. The average particle size of the cellulose fibers is the average of the measured values measured twice for one dispersion using the above method.

The materials used in this example are as follows.
(polypropylene)
A1 (Pellet-like polypropylene): Made by Japan Polypropylene Corporation, Waymax (registered trademark) MFX6, MFR (melt flow rate, temperature: 230 ° C., load: 2.16 kg) 2.5 g / 10 minutes A2 (powdered polypropylene) : A1 is pulverized using a blender (Extreme Mill MX-1200XTS manufactured by Waring Co., Ltd.), classified using a sieve (opening 2.0 mm, wire diameter 0.9 mm), and the particles under the sieve are collected. What I got.

(Hydrophilic cellulose fiber)
B1 (waste paper defibrated product): Recycled paper (moisture content: 12% by mass) crushed using a crusher (Mascoroider (stone mill type grinder) manufactured by Masuyuki Sangyo Co., Ltd.). Average particle size: 64 μm, contact angle with water: 0 degrees

(Cellulose fiber)
C1 (oil palm sky fruit bunch (EFB) holocellulose fiber): Obtained by the following method. 3. Abra palm empty fruit bunch (made in Indonesia, moisture content 12%) crushed to a length of about 1 to 3 cm in a 100 L stainless steel (SUS) tank with an average particle size of 144 μm and a contact angle with water of 0 degrees. Add 5 kg and 39 L of a mixed solvent of ethanol and toluene (ethanol: toluene = 2: 1 (volume ratio)), and stir with a turbine-type stirring blade at a speed of 250 rpm for 75 minutes under the condition of a hot water bath temperature of 80 ° C. The empty fruit bunch was degreased. The degreased oil palm empty fruit bunch was collected by filtering with a stainless steel (SUS) nutche. The same degreasing operation was performed twice more on the recovered oil palm empty fruit bunch. The degreased body of the oil palm empty fruit bunch subjected to such a degreasing operation was dried at 70 ° C. for 5 hours to obtain 4.2 kg of the oil palm empty fruit bunch degreased body.

Next, 3.5 kg of the above-mentioned oil palm empty fruit bunch degreased body and 70 L of ion-exchanged water were put into a 200 L hollow tank, the temperature inside the tank was set to 75 ° C., and the mixture was stirred with a stirring blade at a speed of 80 rpm. , 534 g of acetic acid was added. Subsequently, an aqueous sodium chlorite solution in which 2.8 kg of sodium chlorite was dissolved in 8.8 kg of ion-exchanged water was added to the tank over 3 hours, and the mixture was aged at an internal temperature of 80 ° C. for 1 hour. Further, the operation of adding an aqueous solution of sodium chlorite in which 2.8 kg of sodium chlorite was dissolved in 534 g of acetic acid and 8.8 kg of ion-exchanged water was added to the tank and stirred three times. Then, for the purpose of expelling the dissolved gas, nitrogen gas was bubbled in the tank, allowed to stand overnight, and then the supernatant of the suspension in the tank was extracted. Next, 30 L of ion-exchanged water was put into the tank, stirred for 3 minutes, and the operation of extracting the supernatant of the suspension was performed three times, and then the suspension in the tank was filtered by Nuche. After washing the obtained filtrate with 34 L of ion-exchanged water, the operation of filtering was performed four times. Next, the filtrate was washed with 35 L of a mixed solvent of ion-exchanged water and acetone (ion-exchanged water: acetone = 2: 1 (volume ratio)), and then the operation of filtering was performed twice. Then, after washing with 35 L of acetone, filtration was performed. The obtained delignin form of the oil palm empty fruit bunch was dried at 60 ° C. for 16 hours to obtain 2.5 kg of EFB holocellulose. Finally, the obtained EFB holocellulose was defibrated using a crusher (mass colloider manufactured by Masuko Sangyo Co., Ltd.).

C2 (Methyl methacrylate-treated EFB holocellulose fiber): Obtained by the following method. Average particle size: 218 μm, contact angle with water: 112.7 degrees C1 (EFB holocellulose) 10.0 g and 1 L of distilled water are mixed with a homogenizer (Ultra Turlux, manufactured by IKA) at a speed of 1200 rpm for 5 minutes. The mixture was stirred and the resulting suspension was filtered through a cellulose. 2 L of distilled water was added to the obtained filtrate, and the mixture was stirred again with a homogenizer at a rate of 1200 rpm for 5 minutes, and the obtained suspension was filtered through Nutche. The obtained filtrate was placed in a 2 L eggplant-shaped flask, and 400 mL of distilled water was added to obtain a suspension of EFB holocellulose. Then, while mechanically stirring the suspension of EFB holocellulose, nitrogen gas was blown into the suspension for 10 minutes to degas the suspension. Subsequently, 1.00 g of ammonium cerium nitrate (IV) (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., 036-01742) and methyl methacrylate (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., 139-) were added to the suspension of EFB holocellulose. 02726) 10.0 g was added, and the mixture was stirred under a nitrogen gas stream for 10 hours. After completion of the reaction, the suspension was filtered. After adding 400 mL of distilled water to the obtained filtrate and stirring it, the operation of collecting the filtrate by filtration was repeated 5 times to wash with water. Subsequently, 400 mL of acetone was added to the filtered product washed with water and stirred, and then the operation of collecting the filtered product by filtration was repeated 5 times to perform the acetone washing. The acetone-washed filtrate was vacuum dried at 50 ° C. to obtain 14.2 g of methylated methacrylate EFB holocellulose. Finally, the obtained methylated methacrylate EFB holocellulose was defibrated using a pulverizer (Mascoroider, manufactured by Masuko Sangyo Co., Ltd.).

C3 (n-butyl methacrylate-butylated EFB holocellulose fiber): Obtained by the following method. Average particle size: 198 μm, contact angle with water: 119.7 degrees C1 (EFB holocellulose) 10.0 g and 1 L of distilled water are mixed with a homogenizer (Ultra Turlux, manufactured by IKA) at a rate of 1200 rpm for 5 minutes. The mixture was stirred and the resulting suspension was filtered through a cellulose. 2 L of distilled water was added to the obtained filtrate, and the mixture was stirred again with a homogenizer at a rate of 1200 rpm for 5 minutes, and the obtained suspension was filtered through Nutche. The obtained filtrate was placed in a 2 L eggplant-shaped flask, and 400 mL of distilled water was added to obtain a suspension of EFB holocellulose. Then, while mechanically stirring the suspension of EFB holocellulose, nitrogen gas was blown into the suspension for 10 minutes to degas the suspension. Subsequently, 1.00 g of ammonium ammonium nitrate (IV) and 10.0 g of n-butyl methacrylate (M0081 manufactured by Tokyo Kasei Kogyo Co., Ltd.) were added to the suspension of EFB holocellulose, and the mixture was stirred under a nitrogen gas stream for 10 hours. .. After completion of the reaction, the suspension was filtered. After adding 400 mL of distilled water to the obtained filtrate and stirring it, the operation of collecting the filtrate by filtration was repeated 5 times to wash with water. Subsequently, 400 mL of acetone was added to the filtered product washed with water and stirred, and then the operation of collecting the filtered product by filtration was repeated 5 times to perform the acetone washing. The acetone-washed filtrate was air-dried at room temperature for 12 hours to obtain 14.0 g of n-butyl methacrylate-butylated EFB holocellulose. Finally, the obtained n-butylated EFB holocellulose methacrylate was defibrated using a pulverizer (Mascoroider, manufactured by Masuko Sangyo Co., Ltd.).

C4 (Hexylated EFB holocellulose fiber methacrylic acid): Obtained by the following method. Average particle size: 178 μm, contact angle with water: 118.2 degrees C1 (EFB holocellulose) 10.0 g and 1 L of distilled water are mixed with a homogenizer (Ultra Turlux, manufactured by IKA) at a rate of 1200 rpm for 5 minutes. The mixture was stirred and the resulting suspension was filtered through a cellulose. 2 L of distilled water was added to the obtained filtrate, and the mixture was stirred again with a homogenizer at a rate of 1200 rpm for 5 minutes, and the obtained suspension was filtered through Nutche. The obtained filtrate was placed in a 2 L eggplant-shaped flask, and 400 mL of distilled water was added to obtain a suspension of EFB holocellulose. Then, while mechanically stirring the suspension of EFB holocellulose, nitrogen gas was blown into the suspension for 10 minutes to degas the suspension. Subsequently, 1.00 g of ammonium ammonium nitrate (IV) and 10.0 g of hexyl methacrylate (M0503 manufactured by Tokyo Kasei Kogyo Co., Ltd.) were added to the suspension of EFB holocellulose, and the mixture was stirred under a nitrogen gas stream for 10 hours. After completion of the reaction, the suspension was filtered. After adding 400 mL of distilled water to the obtained filtrate and stirring it, the operation of collecting the filtrate by filtration was repeated 5 times to wash with water. Subsequently, 400 mL of acetone was added to the filtered product washed with water and stirred, and then the operation of collecting the filtered product by filtration was repeated 5 times to perform the acetone washing. The acetone-washed filtrate was air-dried at room temperature for 12 hours to obtain 15.9 g of hexylated EFB holocellulose methacrylate. Finally, the obtained methacrylic acid hexylated EFB holocellulose was defibrated using a pulverizer (Mascoroider, manufactured by Masuko Sangyo Co., Ltd.).

C5 (Dodecyl Methacrylic Acid EFB Holocellulose Fiber): Obtained by the following method. Average particle size: 411 μm, contact angle with water: 131.2 degrees C1 (EFB holocellulose) 10.0 g and 1 L of distilled water are mixed with a homogenizer (Ultra Turlux, manufactured by IKA) at a speed of 1200 rpm for 5 minutes. The mixture was stirred and the resulting suspension was filtered through a cellulose. 2 L of distilled water was added to the obtained filtrate, and the mixture was stirred again with a homogenizer at a rate of 1200 rpm for 5 minutes, and the obtained suspension was filtered through Nutche. The obtained filtrate was placed in a 2 L eggplant-shaped flask, and 400 mL of a mixed solvent (methanol: distilled water = 9: 1 (volume ratio)) was added to obtain a suspension of EFB holocellulose. Then, while mechanically stirring the suspension of EFB holocellulose, nitrogen gas was blown into this turbid liquid for 10 minutes to degas the suspension. Subsequently, 1.00 g of ammonium ammonium nitrate (IV) and 10.0 g of dodecyl methacrylate (M0083, manufactured by Tokyo Kasei Kogyo Co., Ltd.) were added to the suspension of EFB holocellulose, and the mixture was stirred under a nitrogen gas stream for 10 hours. After completion of the reaction, the suspension was filtered. After adding 400 mL of distilled water to the obtained filtrate and stirring it, the operation of collecting the filtrate by filtration was repeated 5 times to wash with water. Subsequently, 400 mL of acetone was added to the filtered product washed with water and stirred, and then the operation of collecting the filtered product by filtration was repeated 5 times to perform the acetone washing. The acetone-washed filtrate was vacuum dried at 50 ° C. to obtain 16.9 g of dodecyl methacrylated EFB holocellulose. Finally, the obtained dodecyl methacrylated EFB holocellulose was defibrated using a pulverizer (Mascoroider, manufactured by Masuko Sangyo Co., Ltd.).

C6 (Hydroxyethyl methacrylate EFB holocellulose fiber): Obtained by the following method. Average particle size: 184 μm, contact angle with water: 0 degrees 10.0 g of C1 (EFB holocellulose) and 1 L of distilled water are stirred at a speed of 1200 rpm for 5 minutes using a homogenizer (Ultra Turlux, manufactured by IKA). , The resulting suspension was filtered through Nutche. 2 L of distilled water was added to the obtained filtrate, and the mixture was stirred again with a homogenizer at a rate of 1200 rpm for 5 minutes, and the obtained suspension was filtered through Nutche. The obtained filtrate was placed in a 2 L eggplant-shaped flask, and 400 mL of distilled water was added to obtain a suspension of EFB holocellulose. Then, while mechanically stirring the suspension of EFB holocellulose, nitrogen gas was blown into the suspension for 10 minutes to degas the suspension. Subsequently, 1.00 g of ammonium ammonium nitrate (IV) and 10.0 g of hydroxyethyl methacrylate (M005, manufactured by Tokyo Chemical Industry Co., Ltd.) were added to EFB holocellulose, and the mixture was stirred under a nitrogen gas stream for 10 hours. After completion of the reaction, the suspension was filtered. After adding 400 mL of distilled water to the obtained filtrate and stirring it, the operation of collecting the filtrate by filtration was repeated 5 times to wash with water. Subsequently, 400 mL of acetone was added to the filtered product washed with water and stirred, and then the operation of collecting the filtered product by filtration was repeated 5 times to perform the acetone washing. The acetone-washed filtrate was air-dried at room temperature for 12 hours to obtain 19.1 g of hydroxyethyl methacrylate EFB holocellulose. Finally, the obtained hydroxyethyl methacrylated EFB holocellulose was defibrated using a pulverizer (Mascoroider, manufactured by Masuko Sangyo Co., Ltd.).

C7 (Cellulose Acetate Fiber): Cellulose acetate fiber (Fujifilm Wako Pure Chemical Co., Ltd., 039-01695, vinegarization degree 55.2%) was solved using a crusher (Masukoroider, Masuyuki Sangyo Co., Ltd.). What was obtained by fiber. Average particle size: 234 μm, contact angle with water: 73.9 degrees

C8 (Cellulose Triacetate Fiber): Cellulose Triacetate Fiber (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., 037-16765, vinegarization degree 61.4%) using a crusher (manufactured by Masuko Sangyo Co., Ltd., Mascoroider). What was obtained by defibrating. Average particle size: 278 μm, contact angle with water: 69.7 degrees

C9 (n-butyl acrylate EFB holocellulose fiber): Obtained by the following method. Contact angle with water: 101.8 degrees C1 (EFB holocellulose) 2.00 g was added with 100 mL of distilled water to prepare a suspension of EFB holocellulose. Then, while stirring the suspension of EFB holocellulose with a stirrer, nitrogen gas was blown into the suspension for 10 minutes to degas the suspension. Subsequently, 200 mg of ammonium ammonium nitrate (IV) and 2.00 g of n-butyl acrylate (manufactured by Wako Pure Chemical Industries, Ltd., 022-03306) were added to the suspension of EFB holocellulose for 12 hours under a nitrogen gas stream. Stirred. After completion of the reaction, the suspension was filtered. After adding 100 mL of distilled water to the obtained filtrate and stirring it, the operation of collecting the filtrate by filtration was repeated 5 times to wash with water. Subsequently, 100 mL of acetone was added to the filtered product washed with water and stirred, and then the operation of collecting the filtered product by filtration was repeated 5 times to perform the acetone washing. The acetone-washed filtrate was vacuum dried at 50 ° C. to obtain 3.90 g of n-butyl methacrylate-butylated EFB holocellulose.

[Example 1]
Weighed 101.0 g of A2 (powdered polypropylene), 51.1 g of B1 (waste paper defibrated product, moisture content 12% by mass), and 4.5 g of C2 (methylated EFB holocellulose fiber). The weighed A2, B1 and C2 were separated into 30 containers, and the separated A2, B1 and C2 were mixed for each container to obtain a raw material mixture. The obtained raw material mixture has an A2 content of 67% by mass, a B1 content of 30% by mass, and a C2 content of 3% by mass.

The above raw material mixture was put into a twin-screw kneading extruder (KZW15-30MG manufactured by Technobel Co., Ltd.), and the die part temperature Y1: 165 ° C. and the cylinder part temperature X1 / X2 / X3 / X4: 165 ° C./165 ° C./165. After kneading under the conditions of ° C./165 ° C. (X1 to X4 are the temperatures of each part from the introduction part of the raw material mixture in the cylinder part to the die part) and the screw rotation speed of 250 rpm, the mixture is extruded from the tip of the die having a diameter of 3 mm. A string-shaped precursor kneaded product (first kneaded product) was obtained.

The obtained first kneaded product was cut to an appropriate length. The obtained cut piece was pulverized using a blender (Extreme Mill MX-1200XTS manufactured by Waring Co., Ltd.). The obtained pulverized product was classified using a sieve (opening 2.0 mm, wire diameter 0.9 mm), and the granular first kneaded product under the sieve was recovered.

The obtained granular first kneaded product was put into a twin-screw kneading extruder (KZW15-30MG manufactured by Technobel Co., Ltd.) and kneaded under the following kneading condition 1. At this time, cold water (5 ° C.) is supplied from between the X2 part and the X3 part of the cylinder into the cylinder at a rate of 2 mL / min, and the first kneaded material and water are supplied between the X3 to X4 parts of the cylinder. It was kneaded to produce a second kneaded product. The produced second kneaded product was extruded from the tip of a die having a diameter of 3 mm, and water was evaporated from the second kneaded product to obtain a strand-shaped foam having a circular cross section.

[Examples 2 to 6, Comparative Examples 1 to 3]
Similar to Example 1, strand-shaped foaming having a circular cross section, except that the type and content of cellulose fibers and the content of B1 (waste paper defibrated product) were changed as shown in Table 1 below. I got a body.

[evaluation]
The density of the obtained foam was measured by the following method. The results are shown in Table 1 together with the composition of the raw material mixture.

(Measuring method of foam density)
A strand-shaped foam is cut perpendicular to the extrusion direction using a razor (GEM, 62-0167), and a test sample for density measurement of a substantially columnar columnar length of 7 to 8 cm is prepared for each foam. Three of each were prepared. The weight and volume of each of the three test samples were measured, and the density ρ (kg / m ³ ) of each test sample was determined by the following formula (1). The average value of the densities of the three obtained test samples was calculated and used as the density of the foam. The mass M (kg) of the test sample was measured in the atmosphere, and the volume V (m ³ ) of the test sample was measured by the underwater substitution method.
ρ = M / V ・ ・ ・ (1)
M: Mass of test sample (kg), V: Volume of test sample (m ³ )

The foams of Examples 1 to 6 containing the hydrophilic cellulose fibers and the hydrophobic cellulose fibers within the scope of the present invention have a lower density, that is, a larger amount of pores, as compared with the foams of Comparative Examples 1 to 3. rice field. Since the foams of Comparative Example 1 and Comparative Example 2 do not contain hydrophobic cellulose fibers, the foaming due to evaporation of water becomes non-uniform during the production of the foam, the foam shrinks, and the density becomes high. It is thought that it was. Since the foam of Comparative Example 3 did not contain hydrophilic cellulose fibers, it is considered that the density was increased because the amount of foam was reduced during the production of the foam. From the above results, it was confirmed that it is possible to obtain a foam having a low density by using the hydrophilic cellulose fiber and the hydrophobic cellulose fiber in combination.

[Examples 7 to 9, Comparative Example 4]
Except that the contents of A2 (powdered polypropylene), B1 (waste paper defibrated product), and C4 (methacrylic acid hexylated EFB holocellulose fiber) were changed as shown in Table 2 below, the contents were the same as in Example 3. Similarly, a strand-shaped foam having a circular cross section was obtained. The density of the obtained foam was measured by the above method. The results are shown in Table 2.

The foams of Examples 7 to 9 in which the contents of B1 (hydrophilic cellulose fiber), C4 which is a hydrophobic cellulose fiber, and A2 (powdered polypropylene) are within the range of the present invention have a C4 content. The density was lower than that of the foam of Comparative Example 4, which was less than the scope of the invention. From this result, it was confirmed that it is possible to obtain a foam having a low density by containing the hydrophilic cellulose fiber, the hydrophobic cellulose fiber and the polypropylene within the range of the present invention.

[Example 10]
67.0 g of A1 (pellet-shaped polypropylene), 34.1 g of B1 (waste paper defibrated product, moisture content 12% by mass) and 3.00 g of C9 (n-butylated EFB holocellulose fiber) were weighed. The weighed A1, B1 and C9 were separated into 30 containers, and the separated A1, B1 and C9 were mixed for each container to obtain a raw material mixture. The obtained raw material mixture has an A1 content of 67% by mass, a B1 content of 30% by mass, and a C9 content of 3% by mass.

The obtained raw material mixture was put into a twin-screw kneading extruder (KZW15-30MG manufactured by Technobel Co., Ltd.), and the die part temperature Y1: 168 ° C., the cylinder part temperature X1 / X2 / X3 / X4: 170 ° C./180 ° C./ The mixture was kneaded under the conditions of 180 ° C./170 ° C. and a screw rotation speed of 60 rpm. At this time, cold water (5 ° C.) is supplied from between the X2 part and the X3 part of the cylinder into the cylinder at a rate of 2 mL / min to produce the first kneaded product between the X1 part and the X2 part of the cylinder. , Kneaded with water between the X3 to X4 parts of the cylinder to form a second kneaded product. The produced second kneaded product was extruded from the tip of a die having a diameter of 3 mm, and water was evaporated from the second kneaded product to obtain a strand-shaped foam having a circular cross section. The density of the obtained foam was measured by the above method. The results are shown in Table 3.
[Example 11]
A strand-shaped foam having a circular cross section was obtained in the same manner as in Example 10 except that C2 (methyl methacrylate-treated EFB holocellulose fiber) was used instead of C9, which is a hydrophobic cellulose fiber. The density of the obtained foam was measured by the above method. The results are shown in Table 3.

[Comparative Example 5]
Except for the fact that the amount of A1 (pellet-like polypropylene) was 70.0 g and the amount of B1 (waste paper defibrated product, water content 12% by mass) was 34.1 g without using C9, which is a hydrophobic cellulose fiber. Obtained a strand-shaped foam having a circular cross section in the same manner as in Example 10. The density of the obtained foam was measured by the above method. The results are shown in Table 3.

Even when the first kneaded product forming step and the second kneaded product forming step are continuously performed, the foams of Examples 10 to 11 containing the hydrophobic cellulose fibers are the foams of Comparative Example 5 containing no hydrophobic cellulose fibers. The density was lower than that of the body.

Claims (5)

It contains hydrophilic cellulose fibers having a contact angle with water of 10 degrees or less , hydrophobic cellulose fibers having a contact angle with water of 50 degrees or more, and polypropylene.
The content of the hydrophilic cellulose fiber is in the range of 10% by mass or more and 60% by mass or less, the content of the hydrophobic cellulose fiber is in the range of 2% by mass or more and 50% by mass or less, and the content of the polypropylene is A foam having a content in the range of 38% by mass or more and 88% by mass or less. The foam according to claim 1, wherein the hydrophobic cellulose fiber is a cellulose fiber whose surface is treated with a hydrophobic agent. The foam according to claim 1, wherein the hydrophobic cellulose fiber is a cellulose acetate fiber having a degree of vinegarization in the range of 30% or more and 63% or less. The foam according to any one of claims 1 to 3, wherein the hydrophilic cellulose fiber is made by defibrating used paper. The foam according to any one of claims 1 to 4, wherein the density is 50 kg / m ³ or less.