JPS6025560B2 - waterproof paper - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a waterproof paper coated with a mixture of a vinyl chloride copolymer emulsion internally plasticized with 25 to 30% ethylene, an alkaline dispersion of zirconium salts and paraffin wax. It is something.

Conventionally, in order to impart waterproofness, water repellency, and heat-sealing properties to paper, paperboard, etc., it has been necessary to extrude olefin-based synthetic resins such as polyethylene or polypropylene and laminate them in the form of a film, or to make them polychlorinated. It is coated with an emulsion or solvent solution of a synthetic resin such as vinyl or polyvinylidene chloride that forms a water-resistant film, but there are problems such as pinholes, so it is necessary to increase the amount of coating or apply two or three coats. method must be taken.

There are also latex-impregnated papers coated with or impregnated with water-resistant synthetic resins, but they are expensive and have poor workability.
The present invention relates to water-resistant paper that completely eliminates pinholes with one application and has good water resistance, water repellency, and heat sealability, and is ideal for packaging materials using paperboard, paper, etc.
In particular, stains caused by oil, moisture, and blood on meat, fish, etc.
The packaging material prevents staining and the penetration of oil and moisture into the packaging, which would cause deterioration of the strength of the packaging material, and has a particularly permanent and stable water repellency that does not cause contamination of the inside of the packaging, and is also heat-sealable. This is what we provide.

It can also be applied to the manufacture of water-resistant corrugated cardboard by kinetically applying it to the surface of the base paper. When the mixed solution of ethylene internally plasticized vinyl chloride copolymer and zirconium salt-paraffin wax emulsion used in the present invention (hereinafter simply referred to as the coating solution) is applied to paper or paperboard, only the zirconium salt-paraffin wax content is applied to paper or paperboard. A portion of it penetrates into the paper and simultaneously closes all the pinholes, and the surface of the paper is laminated with a uniformly mixed film of ethylene internally plasticized vinyl chloride copolymer and zirconium salt-paraffin wax.

In this way, water-resistant paper with no pinholes, water repellency, and heat-sealability can be produced by applying the present coating liquid only once. In addition, even on rough paper with many uneven surfaces, the purpose can be achieved with just one application of this coating solution. The films of general polyvinyl chloride and vinyl chloride IJden are highly "wettable" by water, and if there are pinholes, water can easily enter the inside of the paper through the pinholes. The advantage of using the water-resistant paper of the present invention is that even if there is no leakage from the corner of the tray container as shown in Figure 1, water will not leak with conventional water-resistant paper. If the water reaches the cut edge of the paper, it will crawl up the wall and reach the cut edge a of the paper.
However, with the water-resistant paper of the present invention, water stops at the x position and does not creep up the wall. No. That is, in the present invention, the excellent properties of the ethylene internally plasticized vinyl chloride copolymer are exhibited together with the water repellent effect of the zirconium salt and paraffin wax activated by further heating and drying to a temperature of 7 pi It is possible to obtain coated paper that is waterproof, water-resistant, and heat-sealable. The ethylene internally plasticized vinyl chloride copolymer used in the present invention contains 25 to 30% ethylene.
, an internally plasticized vinyl chloride copolymer containing 75-70% vinyl chloride, whose latex has a solid content of 50% and a pH of 7.1.
~11.0.

On the other hand, the zirconium salt-paraffin wax dispersion used in this invention is a reaction product of zirconyl salt, zirconyl acetate, etc., and stearic acid, palmitic acid, and oleic acid, and is a liquid in which paraffin wax is uniformly dispersed in this. Daiichi Kigen Kagaku Kogyo K.K.) and Coat Sizer-NZ (Daiwa Kagaku Kogyo K.K.) are commercially available. Anything is fine. The mixed composition of the present coating liquid is 99.7 to 80% solid content of the emulsion of ethylene internally plasticized vinyl chloride copolymer and 0.3 to 20% solid content of the zirconium paraffin wax emulsion, preferably It is 3 to 10% relative to 97 to 90% of the above copolymer.

If it is less than 0.3%, sufficient water repellency and film-forming properties are lacking;
If it is 0% or more, heat sealability, liquid stability, and abrasion resistance of the film will deteriorate.

To apply the above-mentioned coating solution, any known coating machine such as a roll coater, air knife coater, or sizeless coater can be used. Evening/Lin or higher, preferably 4
~15th evening/My good.

Next, an example will be described. Example 1 Emulsion with 50% concentration of ethylene internally plasticized vinyl chloride copolymer 9-anchor zirconium salt-paraffin wax emulsion
1 no Miyako (33% solids) antifoaming agent
0.1 part thickener
When 0.7 parts of the above mixed emulsion was applied to 300% paperboard (ivory quality), 260% paperboard (ivory quality), 260% kraft liner, and 300% card stock paperboard with an air knife coater, coated paper having the properties shown in Table 1 was obtained. was gotten.

The values in the parentheses in Table 1 are based on the properties of untreated base paper when coated solely with ethylene internally plasticized vinyl chloride copolymer (
Under the same conditions as above, results as shown in Table 2 were obtained regarding the properties of Aibo lj solid paperboard) and (2) coated with zirconium salt-paraffin wax emulsion alone.

Table 2 above: Items coated with ethylene vinyl chloride copolymer alone have improved water resistance, but have large pinholes and are not suitable for actual use. In the case of emulsion alone, water absorption cannot be suppressed, and R9 to R.

Although the vertical water resistance also decreases during contact with water, the properties of the waterproof paper of the present invention hardly changed even after being in contact with water for 2 hours. The heat sealability of the waterproof paper of the present invention was as follows.

(150q○, 30 pounds/i in 19 seconds) Ivory Craft Liner Card 548 8/15m width
476 446 That is, it can be seen that this is an extremely excellent result. As described above, it can be seen that the waterproof paper of the present invention has good vertical water resistance, water resistance, and heat sealability. The water-resistant paper of the present invention has excellent chemical resistance, oil resistance, and gas barrier properties in addition to water resistance, and since it is mainly composed of ethylene internally plasticized vinyl chloride, it does not require the addition of a plasticizer, and its emulsion is made of zirconium salt-
It mixes well with wax emulsion, and no separation or precipitation is observed. In addition, the resin film contains zirconium salt mixed into the resin layer, so the water repellent effect is permanent, and this coating solution can be applied with just one application without using a trowel to create pinholes on any rough paper. It is extremely economical and easy to process, and the dry film is transparent and has heat-sealing properties, so it has a wide range of applications, and by adjusting the amount of zirconium salt-wax liquid, it can be used with ordinary vinyl acetate-based adhesives. It has extremely great advantages, such as being suitable for use in food products because it can be pasted and is harmless from a hygienic standpoint.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of a corner portion of a paper container for liquid manufactured using the waterproof paper of the present invention. ×...Liquid level position, a...Paper cut edge surface.

Claims (1)

[Claims] 1 Paper or paperboard with internally plasticized vinyl copolymer latex containing 25 to 30% ethylene and 75 to 70% vinyl chloride as a solid content of 99.7 to 80%, and a zirconium salt.
The alkaline dispersion of parafine wax has a solid content of 0.
．． Waterproof paper coated with a uniformly mixed liquid at a ratio of 3 to 20% and dried at 80°C or higher.