JPS61252392A - Composite synthetic paper - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The conductive composite synthetic paper of the present invention is useful as a packaging material for floppy disks, magnetic recording disks, computer magnetic tapes, and the like.

[Prior art]

A composite material made of a resin film and iron foil or aluminum foil has been proposed as a material for a protective envelope that protects floppy disks from electromagnetic interference, so-called EMI.

However, although gravure printing is possible with resin films or metal foils, multicolor offset printing is difficult. Synthetic paper is known as a resin film capable of multicolor offset printing, which has a base layer made of a biaxially stretched film of thermoplastic resin and a paper-like layer made of a uniaxially stretched film of thermoplastic resin containing fine inorganic powder. (Special Publication No. 46-40794, 50
-29738, 50-28114, 53-66
No. 76, No. 52-30390, JP-A-54-7484
No. 2, No. 56-21830, No. 56-118437, No. 56-141339, No. 57-149363,
Publication No. 57-181829, etc.).

In order to improve offset printability, the surface of the paper-like layer of this synthetic paper is further coated with polyethyleneimine, a cationic or amphoteric acrylic polymer containing tertiary or quaternary nitrogen atoms, poly( A surface modifier made of an aqueous solution such as an ethylene/urea polymer or an epichlorohydrin adduct of polyamide is sometimes applied and dried.

This synthetic paper with a multi-layer structure has high mechanical strength because the base layer is biaxially stretched film, and the paper-like layer has many fine voids mainly made of inorganic fine powder due to stretching, making it lightweight. In addition, cracks occur on the surface, and the ink absorption and
Posters, maps, calendars, tracing paper, mounting materials that have excellent adhesion and require water resistance,
Used for paper such as catalogs and labels. In addition, as a product, it is sold under the trade name Yubo FPGJ by Tamago Oil Synthetic Paper■.

Therefore, if this multilayer synthetic paper is used as a resin film and laminated with metal foil, a good electromagnetic shielding material can be obtained.

However, in the multilayer synthetic paper described above, the thermal or plastic resin film is highly oriented [stretching ratio: length x width = (4-8) x (5-1
2)), and this orientation is also such that the paper-like layer is offset in one direction and the base material layer is offset in two directions, so when sewing this into a handbag for transporting a box containing tape. However, when an external stress is applied to the synthetic paper by a needle or thread, the synthetic paper will tear when the orientation direction and the stress direction match, so there is a drawback that it cannot be used in fields where sewing is performed.

Furthermore, when the synthetic paper comes into contact with the tip of the folding guide when producing a floppy disk protective envelope, it may rarely tear in the orientation direction, which is not preferable.

On the other hand, non-functional sheets are also known, which are obtained by heating and pressing a non-woven fabric made from spread short fibers and intertwining them (Japanese Patent Publication No. 37-4993, JP-A No. 53-10704, 5
No. 3-90404, No. 53-119305, No. 53-
No. 122803, No. 56-15500, No. 57-29
No. 700, No. 57-39299, No. 59-70600
(No. 57-61796, No. 57-139597) It is sold under the trade name "Spunbond" by Imajin. This nonwoven fabric sheet is used as postal envelopes and wallpaper.

This nonwoven synthetic paper has the advantage that it can be sewn because it has no directionality and is highly resistant to tearing, but it has the disadvantages of low tensile strength and the inability to perform offset multicolor printing.

Furthermore, short fibers such as rayon, vinylon, nylon, acrylic, etc. with a diameter of 2 to 6 deniers and a fiber length of 2 to 8 mm are intertwined with a binder to produce nonwoven paper (rayon paper, vinylon paper, nylon paper, etc.) using a wet method. Paper) is also known, and this non-woven synthetic paper is used as shoji paper, wrapping paper for Japanese sweets, bolishing paper, and napkins (``Non-woven fabric and its new uses'', November 2, 1960)
Reprinted on the 5th, nonwoven publication Shari. Appendix Index 12-12
(see page).

The nonwoven synthetic paper produced by this wet method has the advantage of being thinner and less bulky than the nonwoven synthetic paper produced by the dry method described above.
It looks similar to shoji paper, and has the disadvantage of being less glossy.

[Problems to be solved by the present invention]

The present invention solves the above-mentioned problems of not being able to sew synthetic paper made of multi-layer oriented film, inability to print in multiple colors on non-woven synthetic paper, low tensile strength, and poor gloss of non-woven synthetic paper made by wet method. In view of these shortcomings, we decided to create a composite by using a synthetic paper made from an oriented film on the outside that is visible to consumers, and laminating synthetic paper or metal paper made by a wet method containing short metal fibers to this. The present invention provides a composite synthetic paper that enables multi-color offset printing and sewing and is endowed with electrical conductivity.

[Specific measures to solve the problem]

The present invention is a composite synthetic paper having at least two layers: a paper-like layer made of an oriented film of a thermoplastic resin containing 8 to 65% by weight of inorganic fine powder, and an electrically conductive layer, wherein at least the electrically conductive layer is made of metal shorts. The present invention provides a composite synthetic paper characterized in that it is a nonwoven paper obtained by paper-making 5 to 100 weight t fibers and 95 to 0 weight % short thermoplastic resin short fibers by a wet process.

(Synthetic paper made of oriented film) This synthetic paper is a crow-like synthetic paper whose paper-like layer is a biaxially stretched film of thermoplastic resin containing fine inorganic powder (Japanese Patent Publication No. 49-1782, No. 54- 31032) or a biaxially stretched thermoplastic resin film as a base layer,
Synthetic paper whose paper-like layer is a uniaxially stretched thermoplastic resin film containing 8 to 65% by weight of inorganic fine powder (Japanese Patent Publication No. 46-40794, Japanese Patent Application Laid-Open No. 57-149363,
No. 57-181829), and the latter multilayer synthetic paper is sold under the trade name 1YUPO FPG' than the egg oil synthetic paper ■.

Although this synthetic paper has two layers, it has a three-layer structure in which paper-like layers of uniaxially stretched film exist on the front and back surfaces of the base layer (Japanese Patent Publication No. 46
-40794), three-layer to seven-layer synthetic paper (Japanese Patent Publication No. 50-29738, Japanese Patent Application Laid-Open No. 57-149363, Japanese Patent Publication No. 57-149363, No. 56-126155, No. 57-181829), the back side is made of propylene/ethylene copolymer or ethylene/(meth)acrylic acid copolymer metal salt (Na, Li).
.

zn, K), synthetic paper having three or more layers having a heat-sealing layer made of a resin having a lower melting point than the base layer resin such as chlorinated polyethylene (Japanese Patent Application No. 15428-1982).
Specification No. 5).

FIG. 1 shows a cross-sectional view of such multilayer synthetic paper (B) as an example. This example shows a synthetic paper in which a coating layer is provided on the surface of the synthetic paper to further improve offset printability. 1), a paper-like layer (2) made of a uniaxially stretched thermoplastic resin film containing 8 to 65 weight of inorganic fine powder is provided on the front and back surfaces, and further, on the surface of this paper-like film layer (2), A primer (3) selected from the group consisting of polyethyleneimine, poly(ethyleneimine-urea), ethyleneimine adduct of polyamine polyamide, epichlorohydrin adduct of polyamine polyamide, and tertiary to quaternary nitrogen-containing acrylic polymer is provided. It is a synthetic paper with a unique structure.

Three-layer synthetic paper is produced by stretching a thermoplastic resin film containing 0 to 50% by weight of inorganic fine powder in one direction at a temperature lower than the melting point of the resin. , a paper-like layer obtained by laminating a molten film of a thermoplastic resin containing 8 to 65% by weight of inorganic fine powder and then stretching the laminated film in a direction perpendicular to the above direction is uniaxially oriented; It is a film with many fine voids, and the base layer is a laminated structure oriented in biaxial directions. Of course, the primer (
A layer of coating agent) may be provided to further improve offset printability. The base layer (1a) of the biaxially stretched film contributes to the balance of strength in the longitudinal and lateral directions of the synthetic paper. Further, a uniaxially stretched film (21tj) with a paper-like layer has a paper-like texture. When the paper-like layer is a biaxially stretched film, it has a pearlescent luster.

Examples of the thermoplastic resin include polyolefins such as polyethylene, polypropylene, ethylene-propylene copolymer, and ethylene-vinyl acetate copolymer,
Poly(4-methylpentene-1), polystyrene, polyamide, polyethylene terephthalate, partial hydrolyzate of ethylene-vinyl acetate copolymer, ethylene-acrylic acid copolymer and its salt, vinyl-17dene chloride copolymer, e.g. Vinyl-vinylidene chloride copolymer, others,
and mixtures thereof.

Among these, polypropylene and polyethylene are preferred from the viewpoint of water resistance and chemical resistance. In addition, when using polypropylene for the base material layer, it is recommended to orient 3 to 25% by weight of a resin having a lower melting point than polypropylene, such as polyethylene, polystyrene, or ethylene/vinyl acetate copolymer, in order to improve stretchability. .

In addition, inorganic fine powders include calcium carbonate, silica,
Diatomaceous earth, talc, titanium oxide, barium sulfate, etc. having a particle size of 0.03 to 16 microns are used.

The stretching ratio is preferably 4 to 10 times in both the longitudinal and transverse directions, and the stretching temperature is such that the resin is homopolypropylene (melting point 164 to 167
℃), 150 to 162℃, high density polyethylene (
When polyethylene terephthalate (melting point 121-124°C) is used, the temperature is 110-120°C, and when polyethylene terephthalate (melting point 246-252°C) is used, the temperature is 104-115°C. In addition, the stretching speed was 50
~350 m/min.

These stretching ratio, stretching temperature, stretching speed, and inorganic fine powder content are such that the smoothness (Bekk index) of the paper-like layer (2) is 3.00.
If the time is selected to be 0 seconds or less, preferably 2,000 seconds or less, the paper-like layer (2) can be marked with a pencil. Also,
Synthetic paper can be fed and discharged easily.

This multilayer synthetic paper is capable of offset printing and gravure printing, and has good writability. The wall thickness of this multilayer synthetic paper is 200 microfron to I.

The synthetic paper made of this oriented film is embossed if necessary.

The thickness of this synthetic paper is 40 to 600 microns.

(Nonwoven paper for conductive layer) Gold layer short fibers (fiber diameter 0.2 to 15 denier, preferably 2 to 6 denier, fiber length 1 to 20 m, preferably 2 to 8 denier)
or short metal fibers and thermoplastic resin fibers (95 weight tons), or short metal fibers and thermoplastic resin fibers (95
If necessary, paper is made by making paper by dispersing short fibers consisting of (below) h. A conductive nonwoven paper is produced by roll pressing at a pressure of 200 kg/cd.

As short metal fibers, those made of aluminum, copper, nickel, zinc, copper, etc. are used.

Short synthetic fibers include nylon, rayon, acrylic,
Examples include polyvinyl alcohol, polypropylene, polyethylene, etc.

During this papermaking, a polyvinyl alcohol fibrous binder or a thermoplastic resin powder such as polyethylene, polyester, polyamide, polypropylene, etc. may be added as a short fiber binder in an amount of 5 to 30% by weight in the aqueous dispersion. Furthermore, pigment,
Plasticizers, adhesion modifiers, dispersants, etc. may also be blended.

The thickness of this nonwoven paper varies depending on the application, but it is 30 microns or more.
A 3m long one is used.

The short metal fibers are used in a ratio of 5% or more by weight in the fibers. If the weight is less than 5 -, the electromagnetic shielding effect will not be sufficient. In addition, alumina paper containing 95% of short metal fibers by weight can be obtained from Mitsubishi Electric ■.

[Composite synthetic paper]

The composite synthetic paper of the present invention has a structure in which the above-mentioned nonwoven paper (2) and synthetic paper (B) made of an oriented film are bonded together with an adhesive (S) in order to take advantage of the advantages of both. (See Figure 1). Liquid primer is used as an adhesive, for example, Toyo Morton's E is used as a polyurethane primer.
L-150 (product name) or BLS-208OA and BL
An example of a polyester-based brimer containing a mixture of S-2080B is AD-503 (trade name) manufactured by the same company. Primer is 0.5-25 ri/W? It is applied so that

Further, hot melt adhesives such as ethylene/vinyl acetate copolymer, low density polyethylene, metal salts of ethylene/(meth)acrylic acid copolymer, so-called Surlyn, chlorinated polyethylene, chlorinated polypropylene, etc. may be used. For this hot melt adhesive, it is necessary to use a thermoplastic resin having a melting point lower than the stretching temperature during the production of synthetic paper made of oriented film. If the hot melt adhesive is used at a temperature higher than the stretching temperature, the synthetic paper may shrink.

When adhering with the primer, the primer may be applied to either or both sides of the nonwoven paper or synthetic paper, and the adhesive may be applied with pressure using a roll.

When using a hot melt adhesive, it may be extruded into a molten film onto a nonwoven paper or synthetic paper using a goo, laminated, and then adhered to the other nonwoven paper or synthetic paper using a pressure roll. In addition, a molten adhesive film is laminated on one or both sides of a nonwoven paper-like material made of intertwined short fibers that is heated and pressurized during the production of nonwoven paper, and synthetic paper is laminated on this and pressed with a roll. It may also be glued.

When forming envelopes and bags, this composite synthetic paper has a conductive layer made of non-woven paper (■) on which a low-container material such as polyethylene, Surlyn, or ethylene/vinyl acetate copolymer is added in order to facilitate heat-sealing when forming envelopes and bags. Providing an adhesive layer made of a film of melting point resin makes processing easier.

The thickness of the composite synthetic paper varies depending on the use, but is 500 microfron or more.

Offset printing (
(on the paper-like layer of synthetic paper), gravure printing (possible on both front and back sides), perforation, and sewing.

〔Effect of the invention〕

The composite synthetic paper of the present invention can be sewn and has the advantage of high tensile strength and tear resistance. In particular, the resistance to tearing is improved above the average of synthetic paper and nonwoven paper.

It also has an electromagnetic shielding effect.

[Example of manufacturing synthetic paper made of multilayer resin oriented film]

Example 1 (1) Calcium carbonate 1 with an average particle size of 1.5 microns was added to polypropylene with a Mento Index (MI) of 0.8.
2 parts by weight (based on the total weight with polypropylene) were mixed, mixed in an extruder set at 270°C, extruded into a sheet, and cooled in a cooling device to obtain a non-stretched sheet.

This sheet was heated to 140°C and then stretched 5 times in the machine direction.

f21 A composition prepared by mixing 55% by weight of polypropylene with a Ml of 4.0 and 45% by weight of calcium carbonate with an average particle size of 1.5 microns was melt-kneaded in another extruder set at 270°C, and the mixture was melt-kneaded in a die. The sheet was laminated by coextrusion on both sides of the 5-fold stretched sheet in the longitudinal direction obtained in (1) above, and laminated. Next, this three-layer laminate was heated to 155° C. and then stretched 7.5 times in the transverse direction to obtain a three-layer film.

(3) After corona discharge treatment is applied to the surface of this three-layer laminated film, a water-soluble polyacrylic antistatic agent "5T-1100" (trade name) manufactured by Mitsubishi Yuka Fine Co., Ltd. is coated with solid content on both surfaces. It was coated and dried so that one side was o, o5y/m3, and then rolled up.

The thickness of the film thus obtained was approximately 109 microns (12.5/84/12.5) and was excellent as a lithographic offset printing film.

Example 2 Table 1 shows the physical properties of the multilayer synthetic paper "YUBO FPGso" (trade name) of egg oil conversion synthetic paper (■).

[Example of manufacturing non-woven paper]

Example 1 10-fold bag of short steel fibers with a diameter of 3 to 4 denier and a fiber length of 4 to 6 m, 80% by weight of polypropylene short fibers with a diameter of 2 to 4 denier and a fiber length of 3 to 6 III m, polyvinyl alcohol with a particle size of 200 to 280 mesh (100 parts by weight of a mixture containing 10% by weight of inder is dispersed in 1,000 parts by weight of water in the presence of a sodium polyacrylate dispersant, and this is made into paper by a conventional method. The wet paper is dried; Melt alcohol binder and combine short fibers to create a wall thickness of 10
A 0 micron conductive nonwoven paper was obtained.

Table 1 shows the physical properties of this nonwoven paper.

Example 2 (for comparison) Table 1 shows the physical properties of Konjin's nonwoven fabric sheet "Spunbon Tona Unicell" (trade name).

In addition, the physical properties of DuPont's nonwoven synthetic paper "Tyvek 1 (trade name)" are shown in the same table.

Example 1 Synthetic paper 1 made of a multilayer oriented film of egg oil conversion synthetic paper
Yubo FPG 80" (trade name) and the conductive nonwoven paper obtained in Example 1 were mixed with Toyo Morton's polyurethane adhesive @BLS.
-208OA and BLS-2080B" mixture
m? <solid content) was used as an adhesive to obtain a composite synthetic paper.

Table 1 shows the physical properties of this composite paper.

Example 2 A low-density polyethylene film was melt-extruded and laminated at 300° C. on the surface of the conductive nonwoven paper side of the composite synthetic paper obtained in Example 1, and this was cooled to obtain a composite synthetic paper.

Using this composite synthetic paper, a protective envelope for a floppy disk was produced by heat-sealing.

The electromagnetic shielding effect of this protective envelope was sufficient.

Example 3 The multi-layer synthetic paper obtained in Example 1 and alumina paper were mixed with Toyo Morton's polyurethane adhesive BLS-208OA and B.
A composite synthetic paper was obtained by laminating with a mixture of LS-2080B.

The volume resistivity of this composite synthetic paper at 23° C. and so% RH was on the order of 1×100.

In addition, offset printability was evaluated by the following method.

Toyo Ink Manufacturing's offset printing ink'''TSP-
400” (product name) and Komori Printing Press Offset 4
Four-color (black, real, red, yellow) offset printing was performed on the polypropylene film surface side of this synthetic paper using a color printing machine, and the ink transferability and ink adhesion were evaluated by the following method.

[Ink transferability]

The halftone dots of each color were magnified (30 times) and the halftone dot reproducibility was visually determined.

Halftone reproduction rate = 100~75chi Good (○) 75~
50% Slightly poor (Δ) 50~0 Poor (×) [Ink adhesion] Adhesive tape made by Nichiban ■ Cellotape # (product name) strongly adheres to the printed surface and quickly peels off along the printed surface. Then, the degree of ink detachment from the paper surface was visually determined.

Ink residual rate: 100~95chi Good (○) 95~
80% Slightly poor (Δ) 80~0 Poor (×) In addition, for sewing properties, those that can be thread-stitched using a sewing machine are rated as good (○), and the synthetic paper will tear due to tension on the thread. The item was marked as defective (x). Δ is normal.

(Margin below)

[Brief explanation of the drawing]

FIG. 1 is a sectional view of the composite synthetic paper of the present invention. In the figure, A is conductive nonwoven paper, Bii multilayer synthetic paper, S is adhesive, 1 is a biaxially stretched film base layer, 2 is a paper-like layer made of Fi-axially stretched film, and 3 is a coating layer. . Patent Applicant Oji Yuka Synthetic Paper Flavoring Company Agent Patent Attorney Hidetoshi Furukawa Agent Patent Attorney Masahisa Hase Figure 1

Claims (1)

[Scope of Claims] 1) A composite synthetic paper having at least two layers: a paper-like layer made of an oriented film of thermoplastic resin containing 8 to 65% by weight of inorganic fine powder, and a conductive layer, the paper comprising at least two layers of a conductive layer; A composite synthetic paper characterized in that the layer is a nonwoven paper obtained by paper-making short fibers of 5 to 100% by weight of short metal fibers and 95 to 0% by weight of short thermoplastic resin fibers by a wet method. 2) The composite synthetic paper according to claim 1, wherein the oriented film of the paper-like layer is uniaxially stretched.