JPH108394A - Paper for press forming and production of formed product by press forming - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain paper for press-forming which has an elongation over a specific value in one direction and enables smooth press-forming without damage even in deep drawing by making paper from a mixture of natural pulp and a specific thermoplastic polymer fiber. SOLUTION: Natural pulp and a polyester sheath-core type conjugated fiber which develops the hot-melt type adhesion at the press-forming temperature are mixed at a weight ratio of 99/1-50/50 and made into paper. The wet paper is given crape with a doctor set to the press roller, then dried with a drier to give the objective paper for press-forming having a unit weight of 10-400g/m<2> , fine wrinkles, waves and other unevenness, and the elongation of >=10% in at least one of the longitudinal and transverse directions measured at 20 deg.C and 65% RH. Two or more sheets of this paper for press-forming are stacked on top of each other and thermally press-formed using the prescribed male and female molds.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a press-formed paper, a method for producing a molded product by performing hot press molding using the press-formed paper, and a press-formed product obtained by the method. More specifically, the present invention relates to a method of manufacturing a deep drawn product having a depth of as much as 50 mm and having complicated irregularities by press molding without causing breakage of paper. The present invention relates to a press-formed paper using natural pulp as a main raw material, a method for producing a molded product by press-forming using the press-formed paper, and a press-formed product obtained by the method.

[0002]

2. Description of the Related Art Conventionally, tray containers for food packaging, packaging containers for electric / electronic parts and other industrial parts have been conventionally used.
Plastic containers such as containers made by pressing foamed polystyrene sheets, containers made by molding foamed polystyrene beads, and containers made using polyvinyl chloride sheets and foams are easy to manufacture. It has been widely used because of its characteristics, mass production, economical efficiency, and so on. However, plastic containers have various problems, such as the generation of harmful gases when incinerated after their use, the generation of high heat during incineration, shortening the life of the incinerator, and remaining undecomposed even when landfilled. In recent years, the processing of used plastic has become a major social problem.

[0003] In view of the above, the above-mentioned packaging containers which have been conventionally produced from plastics have been manufactured by using pulp. For example, egg packaging containers and fruit packaging containers have been used. Pulp containers are actually used. However, in general, natural pulp paper has almost no stretchability. Therefore, if press forming or drawing is performed after the paper is manufactured, the paper breaks and the container cannot be manufactured smoothly. Therefore, when manufacturing a container made of paper (made of natural pulp), a mesh having a depression matching the outer shape of the intended container (for example, a mesh having a concave portion matching the outer shape of an egg) is prepared. Generally, a method of manufacturing (molding) a paper container by wet-making a papermaking raw material including pulp using the mesh pattern, followed by drying. However, this method requires time and effort in the production of paper containers, and is extremely low in productivity, which is one reason that paper containers are not widely used.

Therefore, in order to manufacture paper containers with high productivity, instead of the above-described method for manufacturing paper containers using a mesh, (1) a synthetic pulp of a thermoplastic resin or natural pulp from the synthetic pulp. A method of manufacturing a molded product by subjecting a sheet to a two-dimensional wrinkle in advance and then performing hot press molding (Japanese Patent Laid-Open No. 49-1)
(3265 publication); (2) A method of manufacturing a molded article for packaging by forming corrugated paper from a resin-treated paper material and performing press molding while stretching the corrugated bent portion of the corrugated paper (Japanese Patent Laid-Open No. Hei 5 −2860
JP-A-7-214705); and (3) a method in which a plurality of humidified base papers are superimposed via an adhesive material, and wrinkles are applied thereto, followed by press molding to produce a flat plate molded product (JP-A-7-214705). ); Has been proposed.

[0005] However, the wrinkled sheet obtained by the conventional method (1) is not sufficiently stretchable during hot press molding, and when a deep drawn molded product having a depth of 50 mm is manufactured. In such a case, a hole or break occurs at a corner or the like of the molded product, and a deep drawn molded product cannot be manufactured smoothly. In the case of the conventional method (2) described above, the paper material is formed with corrugated irregularities to give a stretch allowance to the paper material at the time of hot press molding. The stretchability of the paper material at the time is not sufficient, and therefore, in practice, a method is used in which hot press molding is performed after wetting the paper material with corrugated irregularities during hot press molding to increase its elongation. ing. Therefore, a step of rewetting the obtained paper material dried after wet papermaking is necessary, which is complicated in the process, and the paper material to be subjected to hot press molding is in a wet state. Alternatively, it is necessary to dry the wet paper material after hot press molding, and as a result, extra heat and labor are required.

In the case of the conventional method (3),
The humidifying treatment of the base paper as it is, or the humidifying treatment in a state in which a polyethylene laminate layer is provided on at least one side of the base paper, and a plurality of the stencils are overlapped and subjected to press wrinkling, and then press molding is performed. In addition, a process of humidifying the base paper is required, and the process becomes complicated. In addition, since the humidified laminate of base paper is hot-pressed, it must be dried during or after hot-pressing, which results in reduced productivity and high cost in terms of process and thermal efficiency. Inviting. In addition, in the case of the conventional method (3), since the base paper portion is basically made of only natural pulp, it can be said that wrinkles are given, but the stretchability during hot press molding is sufficient. However, it is practically difficult to smoothly manufacture a deep drawn molded product having a depth of up to 50 mm and having complicated irregularities without causing breakage.

[0007] In addition to the above-mentioned conventional techniques (1) to (3), paper containers made by press molding include:
(4) Synthetic resin fibers such as polyethylene and polypropylene and wood pulp are mixed in a ratio of 0: 1 to 1: 1 and 1: 1 to 9: 1.
A paper container (Japanese Patent Laid-Open Publication No. 50-27878) in which two types of synthetic pulp paper are made by mixing at two different ratios to form two types of synthetic pulp paper, laminated in two or three layers, and hot-pressed.
And (5) a laminate comprising a paper substrate having an elongation of 1.8% or more in the vertical and horizontal directions and a heat-resistant synthetic papermaking paper containing an inorganic filler provided on both sides of the paper substrate via an adhesive layer. 2. Related Art A heat-resistant container made of press-formed paper is known.

However, in the above prior art (4), since the purpose is to improve the water resistance of the paper container exclusively, the stretchability of the paper material during press molding is not considered at all. Therefore, the paper material used there is not sufficiently stretchable at the time of press molding, as in the conventional method of (1) above, and a deep drawn molded product having a depth of 50 mm is broken. Can not be manufactured smoothly. Further, although the prior art (5) discloses that an organic resin binder can be used at a rate of 0 to 10% at the time of producing a paper substrate, the content of the organic resin binder is specifically described. Not listed.
The paper substrate actually manufactured by the conventional technique of (5) is a paper substrate made of only wood pulp, and in the conventional technique of (5), a heat-resistant layer having extremely small elongation is formed on the surface of the paper substrate. Is formed, the extensibility of the entire laminate is extremely small, the depth reaches 50 mm, and a deep drawn molded product having complicated irregularities cannot be manufactured smoothly without causing breakage or the like. .

As described in the above-mentioned prior arts (1) to (5), a proposal for manufacturing a molded article such as a container by press-forming paper as it is, without using wet papermaking molding using a mesh mold. Although various processes have been conventionally performed, it is a simple process and has good thermal efficiency, and does not cause breakage of paper at the time of press molding, so that a molded product, particularly, a depth of up to 50 mm and having complicated irregularities. At present, press-formed paper capable of producing deep-drawn molded products and press-forming technology using paper have not been put to practical use yet.

[0010]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a paper having a depth of up to 50 mm and having complicated irregularities even when press-formed in a dry state without wetting the paper. Provided is a press-molding paper mainly composed of natural pulp, which can smoothly produce a deep-drawn molded product with a simple process and good thermal efficiency without causing breakage of the paper. It is. The object of the present invention is to use a paper mainly composed of natural pulp, press-mold the paper in a dry state without wetting, and form a deep-drawn container or the like in a simple process and in a good process. An object of the present invention is to provide a press molding method that can be manufactured smoothly with thermal efficiency. It is a further object of the present invention to provide a press-formed article made of paper mainly composed of natural pulp.

[0011]

Means for Solving the Problems In order to achieve the above object, the present inventors have conducted various studies on paper suitable for press molding from the viewpoint of physical properties and the press molding method. As a result, press-formed paper is produced using natural pulp, and thermoplastic fibers having a thermoadhesive property at a press forming temperature in a specific ratio,
In such press-formed paper, when the elongation of the paper is specified, it has an extremely good stretchability at the time of press forming, and does not tear even when pressed as it is in a dry state, for example, the depth Has reached as large as 50 mm, and it has been found that even a deep drawn molded product having complicated irregularities can be manufactured smoothly. In addition, in performing press molding using the paper, the present inventors may perform press molding using only one sheet of paper, but perform press molding in a state where two or more sheets of paper are stacked. The present inventors have found that forming a molded product by the above method makes it possible to produce the above-described deep-drawn molded product more smoothly, and completed the present invention based on those findings.

That is, the present invention relates to a thermoplastic polymer fiber having a thermal adhesive property with natural pulp at a press molding temperature, wherein natural pulp: the thermoplastic polymer fiber = 99: 1 to 5
A press-formed sheet containing 0:50 (weight ratio), wherein at least one of the longitudinal elongation and the lateral elongation measured at 20 ° C. and 65 RH is 10% or more. Press-formed paper.

[0013] The present invention is a method for producing a molded article, characterized by performing heat press molding using the above-mentioned press-molded paper. The method includes a method in which two or more formed sheets are stacked and press-formed at a temperature and pressure at which the stacked press-formed sheets are laminated and integrated. Further, the present invention includes a press-formed product manufactured by the above method.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail. The press-formed paper of the present invention is mainly composed of natural pulp and thermoplastic polymer fibers. In this case, the type of natural pulp is not particularly limited, and any natural pulp can be used. Examples of natural pulp used in the press-formed paper of the present invention include hardwood pulp, softwood pulp, esparto pulp, Manila hemp pulp, sisal pulp, linter pulp and the like. The natural pulp may be subjected to a treatment such as mercerization. The above-mentioned natural pulp may be used alone or in combination of two or more. Further, the natural pulp may be virgin pulp, used waste paper pulp, or a combination of virgin pack and waste paper pulp. When waste paper pulp is used, for example, those having a long fiber length obtained from milk packs, diaper waste materials, wrapping paper and the like are preferably used. From the point that paper tearing is less likely to occur during press molding,
The natural pulp used for the press-formed paper preferably has a fiber length of about 1 mm or more, more preferably about 2 to 6 mm.

In the press-formed paper of the present invention, it is necessary that the thermoplastic polymer fibers used together with the natural pulp have a thermal adhesive property at the press-forming temperature. The use of thermoplastic polymer fibers that do not have thermal adhesion at the press forming temperature allows the resulting paper to be bonded to natural pulp and to be bonded to the natural pulp and thermoplastic resin, even if pressed under heating. Since the bonding with the united fiber and the bonding between the thermoplastic polymer fibers are not performed by the thermoplastic polymer fiber, the paper cannot have the strength or stretchability that can withstand press molding, and as a result, a molded product with a draw Especially 50m deep
m, and a deep drawn molded product having complicated irregularities cannot be manufactured smoothly without breakage or the like. Here, "having thermal adhesiveness at the press molding temperature" in the present invention means that at the heating temperature during press molding, the thermoplastic polymer fiber softens or melts and adheres to the natural pulp, This means that the polymer fibers adhere to each other to form a bond between the natural pulp and the thermoplastic polymer fibers constituting the paper, thereby improving the stretchability and strength of the paper.

Although not particularly limited, generally, when the press-formed paper of the present invention is used, it is preferably 100
Since the press molding is performed at a temperature of ~ 250 ° C, the thermoplastic polymer fiber used in the press molded paper of the present invention has a
It is preferred that at least a part or all of the surface of the fiber softens or melts at a temperature of ~ 250 ° C. As will be described later, the press-formed paper of the present invention is usually produced by wet-making papermaking raw material containing natural pulp and thermoplastic polymer fibers and then drying the paper. ~ 140 ° C)
It is more preferable that the resin can be softened by the above method and can adhere to natural pulp.

The thermoplastic polymer fiber used in the present invention has a thermoadhesive property at a press molding temperature, and the natural pulp and the thermoplastic polymer fiber have the above-mentioned 99: 1 to 50:
When a press-formed paper is manufactured using a weight ratio of 50, at least one of the longitudinal elongation and the lateral elongation of the press-formed paper is 10% or more at 20 ° C. and 65 RH. Any thermoplastic polymer fiber that can be finally imparted to the molded paper is not particularly limited. The cross-sectional shape of the thermoplastic polymer fiber may be any of circular, irregular, hollow, and the like. Further, the thermoplastic polymer fiber may be a fiber composed of only one kind of thermoplastic polymer, or a composite fiber or a mixed fiber obtained by compounding or mixing two or more kinds of thermoplastic polymers. When it is a composite fiber, it may be a core-sheath type composite fiber, a sea-island type composite fiber, or a side-by-side type composite fiber.

The thermoplastic polymer fiber as described above is not limited, but may be, for example, 140
Thermoplastic polymer fiber having a shrinkage of 20% or more when held at 15 ° C. for 15 minutes, a thermoplastic polymer fiber having a fiber elongation of 20 to 70%, or a heat shrinkage of 20% or more and 20% or more. Thermoplastic polymer fibers satisfying both of the fiber elongation of ~ 70% are preferably used. The “shrinkage rate when the thermoplastic polymer fiber is kept at 140 ° C. for 15 minutes [hereinafter referred to as“ shrinkage rate (140 ° C./15 minutes) ”] is 0.05 mg per thermoplastic polymer fiber. / D refers to the shrinkage ratio with respect to the fiber length before heating when heated and maintained at 140 ° C. for 15 minutes under a load of / d. The fiber elongation of the thermoplastic polymer fiber is measured according to JIS-L-1015.

Further, according to the present invention, the thermoplastic polymer fibers constituting the press-formed paper have a sheath made of a low-melting-point thermoplastic polymer which softens or melts at the temperature at the time of press-forming, and the temperature at the time of press-forming. When the core-sheath type conjugate fiber is composed of a core made of a high-melting thermoplastic polymer that is not softened or melted, the sheath having a low melting point is softened or melted by heat at the time of press molding and joined between natural pulp, Bonding between natural pulp and thermoplastic polymer fiber and bonding between thermoplastic polymer fibers provide high stretchability and strength to press-formed paper that can withstand deep drawing, etc. The core having a high melting point which is not softened or melted at the same time maintains the fiber strength and imparts higher strength and stiffness to the press-formed paper, so that it is possible to obtain a press-formed paper having more excellent press-formability. Arbitrariness. In that case, the ratio of the sheath part to the core part in the core-sheath type composite fiber is generally 30:
It is preferably from 70 to 70:30 from the viewpoint of obtaining press-formed paper having better press-formability, and is preferably 4 to 70:30.
It is more preferable to set the ratio to 0:60 to 60:40.

The thermoplastic polymer fiber preferably used in the press-formed paper of the present invention includes, for example, polyethylene terephthalate fiber; polybutylene terephthalate fiber; modified polyethylene terephthalate fiber; modified polybutylene terephthalate fiber; modified polypropylene fiber;
And a core-in-sheath composite fiber comprising a sheath made of at least one of modified polyethylene terephthalate, modified polybutylene terephthalate, polyethylene and modified polypropylene and a core made of at least one of polyethylene terephthalate, polybutylene terephthalate, polypropylene and polyamide. These thermoplastic fibers may be used alone or in combination of two or more. In particular, if the thermoplastic polymer fiber is a fiber made of an amorphous thermoplastic polymer, its application range is wide, so even if there is a difference in the temperature of the mold during press molding, a desired molded product can be produced. It is preferable because it can be obtained smoothly.

Here, the "modified polyethylene terephthalate" referred to above means, together with the main structural units ethylene glycol unit and terephthalic acid unit, isophthalic acid unit, phthalic acid unit, 2,3-naphthalene dicarboxylic acid unit, 5- Aliphatic dicarboxylic acid units such as aromatic dicarboxylic acid units such as alkali metal sulfoisophthalic acid units, adipic acid units, azelaic acid units, and sebacic acid units; diols such as diethylene glycol units, propylene glycol units, and 1,4-butanediol units It refers to an ethylene terephthalate-based polymer containing a small amount of units and the like (usually 25 mol% or less), and among them, an amorphous ethylene terephthalate-based polymer is particularly preferable. Also,
The “modified polybutylene terephthalate” referred to above is
Aromatic dicarboxylic acid units such as isophthalic acid units, phthalic acid units, 2,3-naphthalene dicarboxylic acid units, and 5-alkali metal sulfoisophthalic acid units together with the main structural units of 1,4-butanediol unit and terephthalic acid unit , Adipic acid units, azelaic acid units, sebacic acid units and other aliphatic dicarboxylic acid units; ethylene glycol units, diethylene glycol units, propylene glycol units and other diol units in small amounts (usually 2
(5 mol% or less). Among them, an amorphous butylene terephthalate polymer is particularly preferable. Further, "modified polypropylene" refers to a propylene-based polymer containing a small amount (usually 30 mol% or less) of ethylene units and unsaturated carboxylic acid units (for example, maleic acid units) together with propylene units, which are main structural units, Amorphous ones are preferred.

In the press-formed paper of the present invention, among the above-mentioned thermoplastic polymer fibers, modified polyethylene terephthalate containing isophthalic acid units at a ratio of 20 to 60 mol% with respect to the total acid component is used. 40% by rate
By using a core-sheath type composite fiber having a non-copolymerized polyester containing in the above ratio, particularly a sheath made of such an amorphous polyester copolymer and a core made of polyethylene terephthalate, press molding is performed. At the time, the adhesion between the fibers, the adhesion between the fibers and the natural pulp are performed well, and the press molding can be performed extremely smoothly. For example, a deep drawing having a depth of 50 mm or more and having complex irregularities Even a molded product can be easily manufactured.

The amorphous polyester copolymer fibers include, for example, (i) a terephthalic acid unit of 40 mol% or more, an isophthalic acid unit of 20 to 60 mol%, and an ethylene glycol unit of 75 mol%. (Ii) the total proportion of aromatic copolymer units other than terephthalic acid units and isophthalic acid units and aliphatic and / or alicyclic copolymer units other than ethylene glycol units Is from 0 to 25 mol% based on all the acid component units in the copolymerized polyester; (iii) the proportion of the aliphatic and / or alicyclic copolymerized units other than the ethylene glycol unit is such that the unit raw material is [ C
Not more than 25% by weight, based on the weight of the copolymerized polyester when it is of the [OH] and / or [OH] type; and (iv)

[0024]

2.83 ≦ log η ₀ ≦ 6.10 5.0 (1 + log [η]) + 0.30 ≦ log η ₀ ≦ 5.0 (1 + log [η]) + 1.30 0.45 ≦ 1 + log [η] ≦ 1.0 [In the above formula, η ₀ is The melt viscosity (poise) of the copolyester under zero shear stress at 160 ° C., [η] indicates the intrinsic viscosity (dl / g) of the copolyester] and the melt viscosity η ₀ and the intrinsic viscosity [η] A copolymerized polyester fiber in which the non-crystalline copolyester component occupies 40% or more in fiber cross-sectional area ratio. Details of the above-mentioned copolymerized polyester fiber are described in JP-A-58-136828.

The above-mentioned thermoplastic polymer fibers used in the press-formed paper of the present invention can be obtained by melt-spinning the above-mentioned thermoplastic polymer by a conventional method. By changing or adjusting the spinning conditions, drawing conditions, heat treatment conditions, and the like, the shrinkage rate (140 ° C./15 minutes) of the thermoplastic polymer fiber is increased to 20% or more, which is the preferable value described above, or the fiber elongation is increased. The degree can be set to the above-mentioned preferable range of 20 to 70%.

Although not limited, in the present invention, the above-mentioned thermoplastic polymer fiber used for press-formed paper preferably has a tensile strength of 3 g / d or more, preferably 4 g / d or more.
It is more preferably g / d or more, and in that case, a press-formed paper that can sufficiently withstand deep drawing press-forming and the like and is more excellent in press-formability can be obtained.

Further, in the press-formed paper of the present invention, since the single fiber fineness of the natural pulp used with the thermoplastic polymer fiber is usually about 0.5 to 30 denier, the balance with the natural pulp is improved. In order to ensure that natural pulp and thermoplastic polymer fibers are uniformly dispersed during papermaking, or to add strength to press-formed paper,
In order to improve the adhesive action at the time of press molding, it is preferable to use a thermoplastic polymer fiber having a single fiber fineness of about 0.5 to 5.0 denier, and about 1.0 to 3.0 denier. It is more preferable to use one. When the single fiber fineness of the thermoplastic polymer fiber is less than 0.5 denier,
The strength of the press-formed paper is reduced, and the paper is liable to be broken during press-forming. On the other hand, if it exceeds 5.0 denier, the function of the thermoplastic polymer fiber as an adhesive is reduced, and it is difficult to bond natural pulp. This makes it difficult to obtain paper having stretchability and strength suitable for press molding.

In the press-formed paper of the present invention, the natural pulp and the thermoplastic polymer fiber are uniformly dispersed at the time of paper making, and the obtained press-formed paper is provided with good stretchability and strength. It is preferable to use a thermoplastic polymer fiber having a fiber length of about 1 to 20 mm,
It is more preferred to use one of about 2 to 7 mm. If the fiber length of the thermoplastic polymer fiber is less than 1 mm, it is difficult to obtain a press-formed paper having stretchability and strength that can withstand press molding, while if it exceeds 20 mm, the dispersibility of the papermaking becomes poor and the heat becomes poor. Paper in which the plastic polymer fibers are uniformly dispersed becomes difficult to obtain, and the quality of the paper tends to be non-uniform.

The press-formed paper of the present invention is obtained by combining the above-mentioned natural pulp and the above-mentioned thermoplastic polymer fiber with natural pulp: thermoplastic polymer fiber = 99: 1 to 50:50.
(Weight ratio), it is necessary to include the
It is preferable to include them at 70:30 (weight ratio). When the proportion of the thermoplastic polymer fiber is less than 1% by weight based on the total weight of the natural pulp and the thermoplastic polymer fiber, the adhesive function of the thermoplastic polymer fiber is not provided, and the stretchability and strength are excellent. Paper cannot be obtained, tearing occurs during press molding, and a deep-drawn molded product with a depth particularly reaching 50 mm cannot be obtained. On the other hand, if the proportion of the thermoplastic polymer fiber exceeds 50% by weight based on the total weight of the natural pulp and the thermoplastic polymer fiber, the shrinkage of the paper during press molding becomes too large, and the resulting press-formed product Is liable to become unstable, and this does not meet the object of the present invention for producing a paper container or the like using as little polymer as possible. In the press-formed paper of the present invention, particularly when the content ratio of the thermoplastic polymer fiber in the press-formed paper is reduced to about 1 to 7% by weight based on the total weight of the natural pulp and the thermoplastic polymer fiber, ,
When a molded article such as a container manufactured from the press-formed paper of the present invention is collected after use, put in water or the like, and stirred, natural pulp is easily collected, so that it can be used again.

As described above, the press-formed paper of the present invention requires that at least one of the elongation in the machine direction and the elongation in the transverse direction measured at 20 ° C. and 65 RH is 10% or more. And preferably 12% or more. If both the elongation in the machine direction and the elongation in the cross direction of the press-forming paper are both 10% or more, the press-formability is further improved. The upper limit of the elongation in the machine direction and / or the transverse direction of the press-formed paper is not particularly limited. However, the elongation in the machine direction and / or the transverse direction of the press-formed paper is considered from the viewpoint of easiness of production of the press-formed paper and cost. Preferably, the degree is set to 500% or less. If both the elongation in the machine direction and the elongation in the transverse direction of the press-formed paper are less than 10%, sufficient elongation is not imparted to the press-formed paper, and the strength tends to be low. The corners and the like are easily broken.

Here, the “elongation” of the press-formed paper referred to in the present invention means the original value when the press-formed paper is pulled in the longitudinal or transverse direction at 20 ° C. and 65 RH until it breaks. It refers to the elongation percentage relative to the length, the specific contents of which are described in the following Examples.

In order to obtain a press-formed paper having the elongation in the machine direction and / or the transverse direction satisfying the above-mentioned values, the natural pulp and the thermoplastic polymer fiber as described above are mixed with natural pulp or thermoplastic resin. Depending on the type and physical properties of the polymer fibers, it can be obtained by mixing and adjusting the weight ratio within the above range to produce paper, but if the elongation of the press-formed paper is not sufficient, When it is desired to impart higher elongation to the press-formed paper, fine wrinkles (crepes), corrugations and other irregularities are applied to the press-formed paper, and the elongation in the vertical direction and / or the horizontal direction is as described above. 1
Press-formed paper of 0% or more can be obtained more smoothly. The application of the fine wrinkles, corrugations and other irregularities described above may be performed by a machine or by hand (for example, hand massage).

The crepe, corrugation and other irregularities may be imparted to the press-formed paper at any stage during and / or after the production of the press-formed paper, for example, in a wet state during papermaking. Or after drying. Among them, when the press-formed paper is still in a wet paper state, when the crepe (fine wrinkles) is applied to the wet paper and the wet paper is dried in that state, the elongation value becomes 10%. The above-mentioned press-formed paper can be obtained smoothly.

Then, crepe, corrugation,
In the case where other irregularities are provided, a direction parallel to the paper length direction, a direction perpendicular to the paper length direction (width direction), a direction oblique to the paper length direction, Any combination of directions may be used, and may be determined according to the shape and structure of the press-formed product to be manufactured.

The press-formed paper of the present invention may be used together with the above-mentioned natural pulp and thermoplastic polymer fiber, if necessary, in a range not interfering with the object of the present invention. Enhancer, wet strength enhancer,
It may contain additives such as a water-repellent agent and a water-proofing agent, fibers other than the above-mentioned thermoplastic polymer fibers, and, if necessary, the surface of the press-formed paper within a range that does not hinder hot press-forming. May be subjected to a treatment such as lamination.

In the press-formed paper of the present invention, the basis weight of one sheet is set to about 10 to 400 g / m ^{2 because} of the processability in paper manufacture, press-formability of paper, and press-forming in press-forming. It is preferable from the viewpoint of handleability, etc., and is 30 to 400.
g / m ² , more preferably 50 to 200 g
/ M ² is more preferable. Further, in the press-formed paper of the present invention, from the viewpoint of further improving the press-formability of the press-formed paper, it is preferable to set the tensile strength in at least one of the longitudinal direction and the transverse direction to 1.5 kgf or more, More preferably, it is set to 2 kgf or more. Further, the dimensions of the press-formed paper of the present invention are not particularly limited, and may be set to a size suitable for manufacturing a target press-formed product.

The method and conditions for producing the press-formed paper of the present invention are not particularly limited, and the paper can be produced by employing a conventionally known paper-making method using natural pulp and paper-making conditions. Although not limited, the press-formed paper of the present invention is, for example, a pulp, beater, disintegrating the papermaking raw material using a refiner or the like to prepare a slurry containing natural pulp and thermoplastic polymer fibers, this slurry One or two types of papermaking nets such as circular nets, short nets, long nets, etc.
Wet paper making is performed by using more than one seed to form wet paper, and it is dried at a temperature of generally 100 to 140 ° C. using a drying machine such as a Yankee dryer or a multi-cylinder dryer, and wound up. Can be manufactured. At this time, in the case where the press-formed paper of the present invention is provided with the irregularities such as the crepe and the corrugation described above, an appropriate method (for example, a drier for drying the wet paper when drying the wet paper) is used. The introduction speed of the is faster than the removal speed from the dryer,
A method using a corrugated embossing roll) may be used to provide the unevenness.

In performing press molding using the press-formed paper of the present invention, one press depends on the type of the molded product and the like.
Press molding may be performed as it is using two pieces of press-formed paper, or press-forming may be performed by stacking two or more press-formed papers. Of these, the basis weight of one press-formed sheet is kept as thin as possible within the range of 10 to 400 g / m ² described above, and two or more sheets, preferably about 3 to 40 sheets, are stacked, and heated under heating. When press forming is performed while pressing and forming, the stacked papers are joined and integrated together, the respective papers are formed, joined, laminated and integrated while stretching well during the press forming, forming a deep drawing A product, for example, a deep drawn product having a depth of up to 50 mm is particularly preferable because it can be manufactured extremely smoothly without causing breakage or the like at its corners.

The molding apparatus used for press molding is not particularly limited, and for example, a press mold composed of a male mold and a female mold can be used as in the conventional press molding. The temperature at the time of press molding is a temperature of 100 to 250 ° C. from the viewpoint of preventing deterioration of natural pulp, thermal efficiency, press moldability, and performing press molding while maintaining good stretchability and strength of press molded paper. Preferably, 11
Preferably, the temperature is between 0 and 180 ° C. As a heating method at that time, even if only the press molding die is heated without preheating the press molding paper, both the press molding die and the press molding die are heated in advance. Alternatively, in some cases, only the press-formed paper may be heated in advance, and the press-formed paper may be pressed by a press-molding die that is not heated. Among them, a method of heating only the press mold is preferable from the viewpoint of processability. The heating method is not particularly limited, for example, a heating method using an electric heater, a hot air heating method, a steam heating method,
A heating oil circulation system or a combination of these systems can be employed, but electric heating is preferred in terms of simplicity.

The pressing pressure and the like are also determined by the type and amount of the thermoplastic polymer fiber used in the press-formed paper, the size and thickness of the target molded product, the number of press-formed papers to be overlapped, and the use of the molded product. can be adjusted depending on, preferably in general, to a 5~500kg / cm ² about the press pressure, it is possible to produce a molded article without causing such damage to the paper, 10~300kg / cm ² Press pressure is more preferable, and 20 to 200 kg / cm ²
Is more preferable. In addition, the press molding time can also be adjusted according to the size and thickness of the target molded product, the number of press-formed paper sheets to be overlapped, the type and amount of thermoplastic polymer fiber used in the press-formed paper, and the like. ,
In general, it is preferable that the pressing is performed at the above-mentioned temperature and the above-mentioned pressing pressure, or that the pressing time is set to about 2 to 20 seconds.

The shape, structure, size, thickness and the like of the molded article produced by the above-mentioned press molding are not particularly limited, and can be appropriately determined according to the use and purpose of the molded article. In general, when the required number of the above-described press-formed papers of the present invention are stacked and press-formed by setting the thickness of the container wall of the press-formed product of the present invention to about 0.5 to 1.5 mm, a good A high-quality molded article having shape retention, high strength, cushioning properties, etc. can be obtained smoothly.

The press-formed product of the present invention can be used as a packaging container for electric / electronic parts and other industrial parts, a buffering container, a tray and a barrel, other various food packaging containers, a paper plate, a paper cup and the like. Press molding of expanded polystyrene sheet,
It can be effectively used in place of plastic molded articles such as molded articles formed by molding using expanded polystyrene beads and molded articles using polyvinyl chloride sheets and foams.

[0043]

EXAMPLES The present invention will be specifically described below by way of examples, but the present invention is not limited thereto. In the following examples, the tensile strength of the press-formed paper and the elongation of the press-formed paper were determined as follows.

Tensile strength of press-formed paper : JIS P8
113.

Elongation of press-formed paper : 20 ° C., 65 RH
Under the conditions described above, the test piece made of press-formed paper is pulled until it breaks according to the tensile strength measurement method of JIS P8113, and the length L just before the press-formed paper breaks is drawn.
₁ and the length L ₀ of the test piece before the tensile test is performed.
And the elongation of the press-formed paper was determined from the following equation.

[0046]

## EQU1 ## Elongation (%) of press-formed paper = ｛(L ₁ −L ₀ )
/ L ₀ ｝ × 100

Example 1 (1) Modified polyethylene terephthalate having an isophthalic acid unit at a ratio of 45 mol% as a sheath, and polyethylene terephthalate as a core, sheath: core =
A core-sheath type composite fiber was manufactured so as to have a weight ratio of 60:40. As a result, the obtained core-sheath type conjugate fiber has a sheath portion having no melting point but softening at 110 ° C., a single fiber fineness of 2 denier, and a shrinkage factor (140 ° C./15 minutes) of 70.
%, Fiber elongation 45%, and tensile strength 4.1 g / d
Was a core-sheath type composite fiber. This core-sheath type composite fiber was cut into a fiber length of 5 mm. (2) 5 parts by weight of the core-in-sheath type composite fiber having a fiber length of 5 mm obtained in the above (1) and 95 parts by weight of waste paper pulp (average fiber length 2.5 mm) extracted from diaper waste materials were used, and water was added thereto. In addition, the mixture was mixed with a pulper to prepare a stock solution having a total concentration of the waste paper pulp and the core-sheath type composite fiber of 0.5% by weight. Wet paper is made, creped with a doctor attached to a press roll, and then passed through a Yankee dryer and then through a multi-cylinder dryer, while keeping the drying temperature of the above two types of dryers within the range of 110 ° C. Thus, a press-formed paper having a crepe with a basis weight of 200 g / m ² was produced. When the elongation of the press-formed paper obtained as a result was measured by the method described above, the elongation in the longitudinal direction was 12.6%, and the elongation in the lateral direction was 3.5%. The press-formed paper had a tensile strength in the longitudinal direction of 2.5 kgf and a tensile strength in the transverse direction of 1.8 kgf. (3) Six press-formed sheets obtained in the above (2) are piled up, and the temperature of the male mold and the temperature of the female mold are both 150 ° C., and the pressing pressure is 100 kg / cm ² using a heating press. Perform hot press molding for 3 seconds.
A press-formed product having a rectangular parallelepiped recess having a width x depth = 50 mm x 30 mm x 20 mm was manufactured. The resulting press-formed product has an average wall thickness of 0.9 m.
m, no breaks occurred at the four corners at the bottom and other places, and the four corners were not thin, resulting in a good finish.

Example 2 (1) Modified polyethylene terephthalate having an isophthalic acid unit at a ratio of 36 mol% as a sheath, and polyethylene terephthalate as a core, sheath: core =
The core-in-sheath type conjugate fiber was manufactured in a weight ratio of 50:50. As a result, the obtained core-sheath type conjugate fiber has a sheath portion having no melting point but softening at 110 ° C., a single fiber fineness of 2 denier, a shrinkage ratio (140 ° C./15 minutes) of 50%,
The core-sheath type composite fiber had a fiber elongation of 50% and a tensile strength of 4.0 g / d. This core-sheath type composite fiber has a fiber length of 5
mm. (2) Example 1 using 5 parts by weight of a core-sheath type composite fiber having a fiber length of 5 mm obtained in the above (1) and 95 parts by weight of waste paper pulp (average fiber length 2.5 mm) extracted from diaper waste material. Press-formed paper having a crepe with a basis weight of 150 g / m ² was produced in the same manner as (2). When the elongation of the press-formed paper thus obtained was measured by the above-described method, the elongation in the vertical direction was 12.7%, and the elongation in the horizontal direction was 5.1%. The tensile strength of the press-formed paper in the longitudinal direction was 2.6 kgf and the tensile strength in the transverse direction was 1.9 kgf. (3) Six press-formed sheets obtained in (2) above were stacked, and press-formed in the same manner as in (3) of Example 1. As a result, a press-formed product having an average thickness of the wall portion of 0.9 mm was obtained, and the four corners at the bottom and other portions were not broken at all, resulting in a good finish.

Comparative Example 1 (1) Polyethylene terephthalate was spun alone and had a softening point of about 90 ° C., a single fiber fineness of 2 denier, a shrinkage (140 ° C./15 minutes) of 60%, and a fiber elongation. Is 257
% And a tensile strength of 1.7 g / d were produced, and the polyethylene terephthalate fiber was cut into a fiber length of 5 mm. (2) Water was added to 3 parts by weight of the polyethylene terephthalate fiber having a fiber length of 5 mm obtained in the above (1) and 97 parts by weight of waste paper pulp (average fiber length of 2.5 mm) extracted from diaper waste materials, and water was added thereto. And then mixing with a pulp to prepare a stock solution having a total concentration of the waste paper pulp and the core-sheath type composite fiber of 0.5% by weight. Wet paper is made by a machine to make wet paper, which is then passed through a Yankee dryer and then through a multi-cylinder dryer, while being dried at a drying temperature of 80 ° C. in the above two types of dryers, and having a basis weight of 70 ° C.
g / m ² of press-formed paper was produced. When the elongation of the press-formed paper thus obtained was measured by the method described above, the elongation in the vertical direction was 3.0% and the elongation in the horizontal direction was 5.5%. Further, the tensile strength of the press-formed paper in the longitudinal direction was 6.5 kgf, and the tensile strength in the transverse direction was 3.0 kgf. (3) Six press-formed sheets obtained in (2) above were stacked, and press-formed in the same manner as in (3) of Example 1. As a result, a press-formed product having an average thickness of the wall portion of 0.8 mm was obtained, but two of the four corners at the bottom were torn, resulting in a poor finish.

[0050]

When the press-formed paper of the present invention is used, a press-formed product having a desired shape and dimensions can be produced extremely smoothly without causing breakage of the paper during press-forming. In addition, it is possible to smoothly produce a deep-drawn press-formed product having a depth of 50 mm, which cannot be obtained by conventional press-forming of paper, and having complicated irregularities. In particular, when performing heat press molding in a state where a plurality of the press-formed papers of the present invention are stacked, it is possible to produce the above-described deep-drawn molded article extremely smoothly without causing breakage of the paper or the like. . And, when the press-formed paper of the present invention is used, the press-forming can be performed in a dry state without being wetted before or during the press-forming, so that the press-forming process is extremely simple, Moreover, since it is not necessary to dry the wet paper, it is advantageous in terms of thermal efficiency. Since the press-formed product obtained by the present invention has good strength and buffering action, it is used for packaging containers for electric and electronic parts, packaging containers for other industrial parts, packaging containers for various foods, paper cups, paper plates. It can be effectively used for various applications such as. The press-formed product such as the packaging container of the present invention has a greatly reduced use ratio of plastics as compared with conventional plastic packaging containers, and therefore reduces various adverse effects that have been caused in used plastics. Or can be eliminated.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kimiaki Shimoyama 5-7-7 Nyorin-cho, Kasugai-shi, Aichi Japan Inside Hi-Pack Co., Ltd. 899-1 Inside Japan Frepa Co., Ltd. (72) Inventor Hideo Hayashi 1-12-39 Umeda, Kita-ku, Osaka-shi, Osaka Inside Kuraray Co., Ltd.

Claims (6)

[Claims] 1. A thermoplastic polymer fiber having a thermoadhesive property at a press molding temperature with natural pulp, natural pulp: the thermoplastic polymer fiber = 99: 1 to 50:50 (weight ratio)
Press-formed paper containing at a rate of 20 ° C, 65R
Press-formed paper characterized in that at least one of the elongation in the machine direction and the elongation in the transverse direction as measured by H is 10% or more. 2. The press-formed paper according to claim 1, wherein the basis weight is 10 to 400 g / m ² . 3. The press-formed paper according to claim 1, which has fine wrinkles, corrugations and other irregularities. 4. A method for producing a molded product, wherein hot press molding is performed using the press molded paper according to claim 1. 5. A method according to claim 1, wherein two or more press-formed papers according to any one of claims 1 to 4 are stacked, and hot press-molded at a temperature and pressure at which the stacked press-formed papers are laminated and integrated. Method for manufacturing molded articles. 6. A press-formed product manufactured by the method according to claim 4.