JPH081078Y2 - Synthetic paper - Google Patents

Description

[Detailed Description of the Invention] Industrial field of application The present invention relates to a synthetic paper which has excellent tear strength and is suitable for various purposes such as wrapping paper and printing paper.
The present invention relates to a synthetic paper having various characteristics such as hiding power, printing characteristics, and lightness required for the synthetic paper.

2. Description of the Related Art Film type is known as one of the conventional synthetic papers. The synthetic paper is made by adding and mixing inorganic compounds such as titanium oxide and calcium carbonate to thermoplastic resins such as polypropylene, polyvinyl chloride and polystyrene. The film was formed by melting.

The problem to be solved by the invention is that the film-type synthetic paper is inferior in terms of mechanical properties because it is formed of a single layer and therefore has a defect that it can be easily torn when a crack is formed. Also, when heat-sealing adhesion is applied during bag-making processing, the strength of the boundary between the adhesive and non-adhesive parts is poor because the resin is a single component, and the range of use for bag-making products by the heel seal method is considerably limited. Met.

The present invention solves this problem, has excellent tear strength, can be sufficiently used for applications requiring mechanical properties, and has sufficient adhesive strength even in the bag manufacturing process by the heat sealing method, and can be widely used. It is intended to provide a synthetic paper that can be used.

Means for Solving the Problem In order to solve this problem, the present invention provides a long-fiber non-woven fabric having a basis weight of 15 to 50 g / m ² made of a core-sheath type composite fiber in which the core component is polyester and the sheath component is polyethylene. Also, a sheet-like material is formed by attaching polyethylene or polypropylene on both sides of a paper with a high concealment degree of 15 to 50 g / m ² .
The sheet material is smoothed by a calendering machine.

Therefore, the non-woven fabric used in the present invention is limited to the long-fiber non-woven fabric from the viewpoints of properties such as strength and flexibility and productivity, and not the short-fiber non-woven fabric. Further, the fibers constituting the non-woven fabric are thermoplastic long fiber filaments composed of core-sheath type composite fibers. The core-sheath type composite fiber may have a circular cross section, a modified cross section such as a triangle or a quadrangle, or a hollow or flat cross section. When a high degree of smoothness is required, the filament cross section is preferably flat, and the flatness ratio is preferably about 2 to 20. Here, the flatness ratio is obtained by flatness ratio = D / T, where D is the width and T is the thickness of the filament cross section.

Next, the single yarn fineness of the core-sheath type composite fiber constituting the nonwoven fabric is preferably 5 denier or less from the viewpoint of smoothness of the sheet-like material, and particularly preferably 1 to 3 denier. The smaller the denier of the single yarn, the more the smoothness of the sheet-like material is improved, but if the fineness is too small, the productivity is deteriorated, which is not preferable.

As the polyethylene constituting the sheath component of the nonwoven fabric used in the present invention, any of linear low density polyethylene, high density polyethylene, medium density polyethylene and low density polyethylene can be used.

On the other hand, the polyester constituting the core component is polyethylene terephthalate whose main repeating unit is ethylene terephthalate or a copolyester.
As the copolymerization component, conventionally known acidic components and glycol components can be used. As the acidic components, isophthalic acid, adipic acid and the like are used, and as the glycol component, propylene glycol, diethylene glycol and the like are used. In addition,
At least ethylene terephthalate units from the aspect of strength
It is preferably 85 mol% or more.

Next, regarding the ratio of the core-sheath component in the composite fiber,
The weight ratio is preferably 1: 0.5 to 5. When the core-sheath ratio is more than 1: 5, the feeling is soft and the adhesive strength of the laminate is improved, but the strength of the resulting nonwoven fabric is lowered, which is not preferable. On the other hand, when the weight ratio is less than 1: 0.1, the strength is excellent, but the adhesiveness is poor, which is not preferable.

The basis weight of the nonwoven fabric is required to be in the range of 15 to 50 g / m ^2, lower the strong tear synthetic paper because a small amount of fibers is less than 15 g / m ^2. On the other hand, when it exceeds 50 g / m ² , the synthetic paper has a large basis weight and becomes thick, which is not preferable for the use of synthetic paper.

On the other hand, as the paper used as the intermediate, cigarette paper and straw packaging paper are most suitable in terms of light weight, hiding power and adhesiveness. Further, depending on the concealing property as a synthetic paper and the need for mechanical properties, the weight per unit paper can be freely combined within the range of 15 to 50 g / m ² . If it is less than 15 g / m ² , the hiding power is poor and the strength is insufficient, so there is a problem in laminating with a non-woven fabric, while if it exceeds 50 g / m ² , there is a problem in delaminating the paper, and synthetic Since the weight of paper is large and thick, it is not preferable for synthetic paper applications.

Next, both polyethylene and polypropylene used as an adhesive between the non-woven fabric and the paper have sufficient adhesive strength, but they can be freely selected according to the need of mechanical properties as the synthetic paper. If the hardness of the synthetic paper is required, polypropylene is suitable, while if softness is required, polyethylene is suitable. Further, depending on the necessity of the degree of hiding as a synthetic paper, the degree of hiding can be remarkably improved by adding 5 to 20% by weight of titanium oxide to the base resin. If it is less than 5% by weight, the degree of hiding cannot be expected, and if it exceeds 20% by weight, the adhesive strength may decrease.

The synthetic paper of the present invention is a sheet formed by laminating non-woven fabric on both sides of the paper with polyethylene or polypropylene, but from the viewpoint of productivity, an extrusion type laminating machine is used, and the above polyethylene or polypropylene is also required. 5 to 20% by weight of titanium oxide is melt-extruded according to the above and applied to one of the adherends in a thickness range of 5 to 50μ, and then the other adherend is bonded before the resin solidifies. Method is preferred. The coating amount may be appropriately determined depending on the nonwoven fabric and the paper to be laminated, but it is usually desirable to coat the same amount or more of the adhesive in order to prevent delamination.

Next, for smoothing the sheet-like material, a calendering machine comprising a combination of a mirror-finish metal roll and a cotton roll, a mirror-finish metal roll and a plastic roll, or an elastic roll is preferably used. The smoothing conditions may be appropriately determined depending on the weighted core / sheath ratio of the non-woven fabric and the type of adhesive, but the calender conditions used in the present invention are preferably a roll temperature of 80 to 110 ° C. and a linear pressure of 150 to 200 kg / cm.

As a method for producing a long-fiber non-woven fabric, while stretching the melt-spun fiber using an air jet, after opening the fiber using a conventionally known filament opening device, it is deposited on a moving mesh body and transferred. A so-called spunbond method in which a non-woven sheet is obtained by producing a non-woven web by subjecting the web to a non-woven sheet, followed by pressing the web with a temporary pressure roller and then heat-pressing with an embossing roller can be preferably used.

 Hereinafter, the present invention will be further described with reference to the drawings.

FIG. 1 is a perspective view of the synthetic paper of the present invention. A long fiber non-woven fabric 1 made of a core-sheath type composite fiber is attached to both sides of a light weight paper 2 having a high degree of concealment via an adhesive layer 3 made of polyethylene or polypropylene to form a laminate, and the surface of the laminate. It has been smoothed by calendering.

Action Synthetic paper having the above-mentioned configuration, the polyester portion which is the core component of the core-sheath type composite fiber constituting the non-woven fabric does not melt,
Since it remains in the synthetic paper in the form of fibers, it acts as an aggregate of the laminate, and because the fibers are randomly arranged, it is considered that the tear strength is improved as compared with the conventional film type. Further, by setting the heat-sealing temperature lower than the melting point of polyester used as the core component during bag-making processing, the polyester in the seal part acts as an aggregate and also sufficiently acts on the strength of the boundary between the seal part and the non-seal part. .

Furthermore, regarding the hiding power of the synthetic paper, it is possible to freely adjust the hiding degree of the synthetic paper by selecting the paper that is sandwiched in the center and, if necessary, by adding titanium oxide to polyethylene or polypropylene that is an adhesive agent. . In addition, it is also excellent in printability due to the porosity of the non-woven fabric, and has the same level of printing characteristics as film-type synthetic paper.

Effects of the Invention As described above, the synthetic paper of the present invention has excellent tear strength, can be sufficiently used in applications requiring mechanical properties, and has sufficient adhesive strength even in bag making processing by the heat sealing method. And can be used in a wide range.

[Brief description of drawings]

 The drawing is a perspective view of the synthetic paper of the present invention. 1 ... long fiber non-woven fabric, 2 ... paper, 3 ... adhesive layer.

Claims (1)

[Scope of utility model registration request] 1. A long-fiber non-woven fabric having a basis weight of 15 to 50 g / m ² made of a core-sheath type composite fiber having a core component of polyester and a sheath component of polyethylene and having a basis weight of 15 to 50 g / m ^{2 and} a high concealment degree. Synthetic paper obtained by laminating polyethylene or polypropylene on both sides of a paper to form a sheet, and smoothing the sheet with a calendering machine.