JPS6075700A - Heat sealable parchment paper having air permeability - 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 The present invention relates to an air-permeable, heat-sealable .xi.-timent paper.

, 6-Timento paper has excellent water resistance, oil resistance, and tasteless and odorless properties, so it is widely used in the food packaging field, especially in the packaging of tartar and margarine, the inner packaging of canned goods, and the packaging of marine products. It is being Because the surface of ξ-timento paper is covered with a thin film of amyloidized natural pulp,
Compared to regular paper, it has excellent water resistance, oil resistance, chemical resistance, and strength, and low air permeability.

In some packaging applications, such as packaging for insect repellents, deodorants, oxygen absorbers, fruits and vegetables, etc., paper that retains a certain degree of air permeability that paper inherently has is preferable.

Further, in order to simplify the packaging process, heat-sealable paper is desired.

As air-permeable parchment paper, it is possible to use mechanically perforated paper, but this tends to reduce its strength because it damages the paper fibers, and it also has the disadvantage of causing unevenness in the paper. There are some types of paper that are partially coated with a substance that does not allow sulfuric acid to permeate, such as polyvinyl alcohol, and then treated with sulfuric acid after drying to produce ξ-timented paper with parts that have not been made into parchment. It has the disadvantage that the parts that are not colored stand out white, making it difficult to obtain uniform air permeability.

E-timent paper with heat-sealing properties can be made by laminating a film of a substance that exhibits heat-sol properties, such as a thermoplastic synthetic resin, or by laminating it with a film of a solution, emulsion, or
There are some types of paper in the form of suspensions that have a thermal seal layer, but the air resistance of these papers naturally decreases. In addition, Japanese Patent Application Laid-Open No. 55-51898 describes a paper made by combining natural and 6 Luso with synthetic pulp and treated with sulfuric acid to produce ξ-timento paper with excellent stability when wet.
There is a description that it is possible to heat 7-years if synthetic paper is selected, but although this paper is slightly more air permeable than normal ξ-timento paper, it is sufficient for practical use. Not.

The inventors discovered that parchment paper has sufficient air permeability, can be heat-sealed, and that the performance deterioration of the inherent properties of parchment paper, such as water resistance, oil resistance, and high strength, is within a range that does not pose a practical problem. As a result of research into parchment paper that is free from inconveniences such as unevenness and non-uniformity, the present invention was arrived at.

That is, in the present invention, natural ξ pulp and thermoplastic synthetic resin pulp, which are composed of 50 to 90% by weight of natural ξ pulp and 50 to 61% by weight of thermoplastic synthetic resin pulp, are thermally fused to each other. It is parchment paper that has been treated with sulfuric acid and has no mechanical perforation, and has an average diameter of 1
It has air permeability with pores of 0 to 100μ distributed at a rate of 50 to 1000/cm, and is heat sealable.
- It is paper.

In the present invention, the average diameter refers to the average of the long diameter and short diameter of the pores. Parchment paper with such a structure has appropriate air permeability and can be heat-sealed, and the performance of parchment paper's original properties such as water resistance, oil resistance, and high strength is reduced by 20%. It is within the range of practical use, and there is no problem at all.

The natural pulp referred to in the present invention includes wood pulp, bast fibers such as beach, mitten, deerskin, manila hemp, etc., but is not limited to the above-mentioned ones. It's not something you can do.

The thermoplastic synthetic resin used in the present invention, 6-Ruzo, may be any resin that is made of a thermoplastic synthetic resin and can be dispersed in water to cause even slight entanglement with natural 6-ruzo, such as polyethylene, polyzolopyrene, etc. I soleolefin resin, polyester resin, solivinyl alcohol, ? Examples include short fibers made of lyamide resin, polystyrene resin, etc., split yarns, fibril P, etc., but are not limited to these. Among these, low softening point polyester resins and polyolefin resins are preferred because they allow heat sealing at low temperatures. The product names include Raleyester (polyester) manufactured by Kuraray Co., Ltd. and Mitsui Nana Rabakku (polyester).
Examples include SWP (polyethylene) manufactured by Daiwabo Co., Ltd. and PolyZoro (polypropylene) for film-forming paper manufactured by Daiwabo Co., Ltd.

These thermoplastic synthetic resins are made from natural pulp of 50~
It is necessary to mix and use 50 to 10% by weight with respect to 90% by weight. If it is less than 10% by weight, the heat sealability will not be sufficient, and if it is more than 50% by weight, the JR fit of the paper will become close to that of a synthetic resin film, and the characteristics of ξ-timento paper will be lost.

The thermoplastic synthetic resin/ξulp must be heat-fused to the natural pulp. If the paper is fused and sticky, the strength of the paper will decrease, which may cause problems in practical use. Furthermore, as will be described later, when pores are generated by processing with sulfuric acid, it becomes difficult to adjust the size and number of 11ll pores.

As the average diameter of pores increases or the number of pores increases, air permeability improves, but water resistance, curvature, and strength decrease.
The opposite is true as the average diameter of the pores decreases or the number of pores decreases. In order to obtain performance suitable for practical use, it is necessary that the average diameter of the pores be 10 to 100 microns, and that the number of pores be distributed over the entire surface at a rate of 50 to 1000 pores/cm''.

Among these, a preferable range is that the average diameter of the pores is 20 to 70.
μ, the number of pores is 100 to 500/crn2.

The following method is preferred for producing the ξ-thimene I paper of the present invention. That is, 50-90% natural
, 50 to 10% by weight of thermoplastic synthetic resin ξruzo, and if necessary, add adhesives, paper strength enhancers, fillers, dyes, and other additives, and then press the paper machine using a regular Fourdrinier paper machine or a circular mesh paper machine. After paper is made with a paper machine, it is dried at a temperature above the softening point of the thermoplastic synthetic resin Zorzo, and then it is dried at a temperature of 00 to 2.
In this method, the material is treated with sulfuric acid at a concentration of 60 to 80% by weight at 0°C for 1 to 10 seconds, followed by neutralization, washing with water, and drying. The sulfuric acid treatment may be carried out in one stage, but first the sulfuric acid treatment is carried out at 0-15℃ and at a concentration of 60-65℃.
A two-step process in which the product is treated with Wj acid at a concentration of 65% to 80% by weight at a temperature of 15 to 20 DEG C. can provide a product with even more uniformity.

If the amount of thermoplastic synthetic resin/Zorzo is increased, the number of pores will increase, and if the amount is decreased, the number of pores will decrease.

The thicker the paper, the fewer the number of pores, and the thinner the paper, the more. If the freeness of natural/e-ruzo is increased, the average diameter of the pores will become smaller, and if it is lowered, it will become larger. The average diameter and number of pores can be controlled by the means described above.

Taking advantage of its characteristics, the .xi.-timento paper of the present invention can be used for packaging insect repellents, deodorants, desiccants, oxygen absorbers, fruits and vegetables, etc. that require air permeability and moisture permeability. It can also be used by forming into paper cartons using thermosoles.

Hereinafter, the present invention will be explained in more detail by giving examples, but the scope of the present invention is not limited by these examples. In addition, parts and % represent serious danger parts and serious 11%.

Example 1 Short sleeve ξ - freeness 27°5R (JIS P-8121
) beaten natural ξol (commercially available N-BSF 50%, L
-I3KF50%) 60 parts of low softening point polyester resin synthetic pulp (Raleyester EP-20 manufactured by Kuraray Co., Ltd.)
1×5, softening point 100° C.), a small amount of a synthetic adhesive was added, and a paper having a basis weight of 3597 m 2 was made using a cylinder Yankee dryer paper machine (dryer surface temperature 110° C.). Subsequently, this paper was immersed in 63% sulfuric acid at 10°C for 3 seconds, then immersed in 67% sulfuric acid at 18°C for 3 seconds, washed with water, neutralized with an aqueous alkaline solution, and further washed with water. After dehydrating with a roll, the surface temperature is 100'
It was dried with a multi-barrel dryer (C) to obtain ξ-timento paper. This paper has an average diameter of 25 to 6 ol.
Microscopic observation of the paper revealed that there were 300 pores/cm3. The synthetic ξ ruzo was thermally fused to the natural ξ ruzo. The performance of this ξ-Timent paper was as shown in Table 1.

Table 1 (Note) T-peel strength was measured by applying pressure for 2 seconds using Fuji Seisakusho Heat Sealer Model 210 (maximum temperature 180°C).

Example 2 55 parts of natural pulp and polyethylene resin synthetic pulp (SWP E-400 manufactured by Mitsui Zera Zotsuku Co., Ltd., softening point 1)
26℃), and the dryer surface temperature was set to 135%.
The operation was exactly the same as in Example 1 except that the temperature was changed to ℃.
A ξ-timento paper was obtained. This .xi.-timento paper had pores with an average diameter of 25 to 70 microns at a ratio of 450/crJI2. The synthetic pulp was heat-fused to the natural pulp. The air permeability and heat seal strength of this parchment paper were as shown in Table 2.

Example 3 35 parts of polypropylene resin synthetic resin (Daiwa Boseki Co., Ltd. polypropylene for membrane paper making, softening point 140°C) was blended with 65 parts of natural polymer (commercially available L-BKP 100%), and the surface temperature of the dryer was adjusted. Exactly the same operation as in Example 1 was performed except that the temperature was 1so DEG C. to obtain ξ-timent paper. This ξ-timento paper has 2 pores with an average diameter of 20 to 60μ.
The synthesized ξruzo was present at a ratio of 60 pieces/cm'' and was thermally fused to the nine natural pulps.The air permeability and heat seal 11 strength of this parchment paper were as shown in Table 2.

Table 2 Examples 4 to 6 75 parts of natural pulp and low melting point polyester resin 2
5 parts natural, 65 parts low melting point polyester resin.
The same procedure as in Example 1 was carried out except that three types of raw materials were used: 35 parts of luzo, 55 parts of natural pulp, and 45 parts of low melting point polyester resin, to obtain zotimento paper. The synthetic pulp was heat-fused to the natural ξ.

These gift papers have pores with an average diameter of 25 to 60 μm, 1507 cm” and 220 pores/c, respectively.
m", 470 pieces/(,y++"), and the air permeability is 120 seconds/100ytl, respectively.
, 65 seconds/100. ql, 22 seconds/xooml.

Comparative World 1 ξ-timento paper was produced by carrying out exactly the same operation as in Example 1 except that paper was made using only natural ξ-ruzo. This paper has almost no pores and has an air permeability of 1000 seconds/100m.
J or higher, and there was no heat sealability at all.

Comparative Example 2 A ξ-timento paper was produced by carrying out exactly the same operation as in Example 1 except that the surface temperature of the P dryer was changed to 90°C. There was no fusion between the natural ξrzo and the synthetic/elp. The air permeability of this paper is 800 seconds/1 o o ml
The tensile strength was only approximately 50% of the value shown in Table 1. This paper had pores with an average diameter of 10-20μ, but less than 20 pores/cm2.

Patent applicant: Asahi Kasei Industries, Ltd.

Claims (1)

[Scope of Claims] ■. Natural ξ consisting of 50 to 90% by weight of natural ξ and 50 to 10% by weight of thermoplastic synthetic resin ξ.
Do not apply sulfuric acid treatment to the paper with thermoplastic synthetic resin/ξlup heat-sealed to the loop, and do not perform mechanical perforation A.
- Chimento paper, which has air permeability and has pores with an average diameter of 10 to 100μ distributed at a rate of 50 to 100 pores/cm2, and is heat sealable /ξ-Timento paper 2 As a thermoplastic synthetic resin pulp The ξ-timent paper according to claim 1 which uses a low softening point polyester resin & the ξ-timent paper according to claim 1 which uses a polyolefin resin as the thermoplastic synthetic resin pulp