JP3511800B2 - Wax-coated paper and method for producing the same - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to water-repellent and moisture-proof paper and paperboard, and a method for producing the same, and more particularly to paper or paperboard coated with wax and a water-soluble polymer.

[0002]

2. Description of the Related Art Many of papers and paperboards for packaging are required to have water repellency and moisture resistance, such as cardboard boxes, paperboard boxes,
Cardboard liner base paper used for craft bags, etc.
Paper and paperboard obtained by applying a water-repellent agent and a moisture-proofing agent to the surface of white paperboard, kraft paper, etc. and drying have been used for a long time.
In order to impart water repellency and waterproofness to the surface of paper, a method of applying wax or laminating a resin is known, but considering the ease of production, printability, and suitability for production. It is most rational to apply a water repellent / moisture preventive agent centered on wax.

Therefore, there are many disclosures of a technique relating to paper coated with wax, and in recent years, JP-A-5-156208 discloses
JP-A-5-295200 and JP-A-5-295316
JP-A-6-313295, JP-A-7-26495
There are issues, etc.

If only the wax is applied to the paper, the surface strength of the paper is insufficient, and it is preferable to use a water-soluble polymer together. The water-soluble polymer substance contributes not only to improving the surface strength, but also to adjusting the viscosity of the wax emulsion, improving moisture resistance by sealing, and improving folding endurance.

At this point, it is necessary to apply a process of applying wax to the surface of the paper / paperboard and then heating and drying with a roll or hot air, but at that time, there is a problem that the wax adheres to a dryer roll or a dryer canvas. . This problem is particularly important when a mixture of wax and water-soluble polymer substance is applied to the surface. Further, not only the drier at the time of paper production, but also the laminating machine at the time of producing a corrugated board sheet, the printing machine for white paperboard, etc., has a problem that the wax adheres to various rolls and hot plates.

[0006] The above-mentioned prior patents relating to wax-coated paper do not show any measures against the above problems. However, not only wax-coated paper but generally a technique for applying a release agent to rolls, which is disclosed in JP-A-60-231894, is known as a measure for deposits on rolls and canvases of paper machine dryers. Has been.

Although it is expected that applying a release agent to the dryer is also effective for the problem of the present case, it requires a release agent supply device to the dryer, and as described above, such as corrugated cardboard bonding. There is the inconvenience of requiring a separate treatment for troubles at other locations.

[0008] Therefore, an object of the present invention is to effectively eliminate the trouble of sticking to various rolls, canvas, etc. in the paper coated with wax and the water-soluble polymer substance.

[0009]

In order to solve the above problems, the present invention adopts the following configurations. That is, the present invention is as follows.
Three inventions. (1) A mixture of wax, water-soluble polymer, and silicone oil , where wax: water-soluble polymer
Is 90:10 to 30:70, which is
Wax coated paper obtained by applying and drying a mixture containing 0.3 to 5% by weight of corn oil . ( 2 ) The wax-coated paper according to invention 1, wherein the water-soluble polymer substance is polyvinyl alcohol. ( 3 ) Invention 1 in which an aqueous liquid containing a wax, a water-soluble polymer and silicone oil is applied to the surface of paper and dried.
A method for producing the wax-coated paper according to any one of 1 to 3 .

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The paper to which the present invention is applied is not particularly limited as long as it is a paper or paperboard that can be used for packaging. Among them, kraft paper for bags, white paperboard, liner base paper for corrugated board, etc. are typical. This is a typical example. Also, the pulp used for them is not particularly limited.

The wax used in the present invention is so-called natural wax and synthetic wax, and the natural wax may be any of vegetable wax, animal wax and mineral wax, for example, wooden wax, cotton wax, carnauba wax, beeswax, wool. Law,
Examples thereof include whale oil, montan wax, lanolin, ozocate, and petroleum wax. Typical petroleum waxes are paraffin wax and microcrystalline wax. As synthetic wax, polyethylene wax,
Examples thereof include oil-based synthetic wax and fatty acid amide-based synthetic wax.

In the present invention, the wax is applied to the paper as a so-called wax emulsion in the form of an aqueous dispersion.

In the present invention, the water-soluble polymer substance refers to a natural or synthetic polymer substance which can exist in the form of an aqueous solution at room temperature, and examples thereof include starch, modified starch, casein, sodium alginate, polyvinyl alcohol, Examples thereof include polyacrylamide, polyethylene oxide, methyl cellulose and carboxymethyl cellulose. Among them, polyvinyl alcohol is most preferable from the viewpoint of surface strength and folding endurance of paper. In the case of polyvinyl alcohol, the degree of polymerization is preferably in the range of 200 to 3000.

[0014] The ratio between the wax and the water-soluble polymer in the present invention is in a solid weight ratio of 90: 10-30: 70
is there. When the wax ratio exceeds 90, the surface strength and the folding endurance are weakened, which is not preferable. Also, the wax is 30
If it is less than, the waterproofness and water repellency are insufficient. In particular, from the balance of water repellency and surface strength, wax: water-soluble polymer =
70: 30-40: 60 are the most preferable.

The silicone oil used in the present invention may be any of those mainly composed of a polymer of an organosiloxane. Therefore, the silicone oil of the present invention includes a straight type silicone oil represented by the following <Chemical formula 1> and a modified silicone oil represented by the following <Chemical formula 2>. In any case, the degree of polymerization (n in chemical formula 1 or chemical formula 2
N + m) of about 5 to 500, the viscosity of the oil itself (25
It is easy to use one having a temperature of about 10 to 10,000 cp.
The silicone oil may be added as it is to the wax emulsion, or may be previously made into an aqueous dispersion with a surfactant. Further, for example, an aqueous emulsion of a modified silicone oil sold as a roll release agent, a water repellent for fibers, a softening agent for fibers and the like may be used.

[0016]

[Chemical 1]

[0017]

[Chemical 2]

[0018] Silicone oils, blend in the range of 0.3 to 5% by weight relative to the wax solids. 0.3% by weight
If it is less than the above range, the effect of preventing adherence of sticky substances is poor, and if it is mixed in excess of 5% by weight, problems such as deterioration of printability and slipping of paper may occur.

The mixture of wax, water-soluble polymer and silicone oil has a dry solid content of 0.2 g / m ² to
The coating amount is about 1.5 g / m ² . The coating amount depends on the purpose, a simple liner for water repellent cardboard for repelling axis water is 0.2g / m ² ~0.7g / m ² or so, when the waterproof paper is more coating .

[0020]

EFFECTS OF THE INVENTION According to the present invention, when a paper having water repellency and waterproofness is made into paper, a dryer roll stain and a canvas stain when applying and drying an aqueous liquid of wax and a water-soluble polymer substance are prevented. . Further, by using the paper of the present invention as a liner base paper for corrugated board, it is possible to prevent roll stains and canvas stains caused by wax in a corrugated board pasting machine.

[0021]

EXAMPLES The present invention will be further described below with reference to examples. In the present examples, the following substances were all used, and in each example, only the mixing ratio was changed. A: Wax Wax emulsion manufactured by Japan PMC (paraffin wax solid content 30%) B: Polyvinyl alcohol Denka K-17 C: Silicone oil Taiho Kogyo Silicone emulsion, Clyclean EC6

In this example, a liner base paper for corrugated board mainly composed of unbleached kraft pulp (220 g / m 2 tsubo)
² ) is applied by an on-machine bar coater to a wax solid content of 0.6 g / m ^2, and dried in a normal paper machine drying zone.

The wax coated liner produced was measured for the following items, and the results are summarized in Table 1. In Table 1, the concentrations of wax (Wax) and polyvinyl alcohol (PVA) are pulp slurry total weight.
It is a value (unit:%) for the amount. In addition, the concentration of silicone
The degree is a value based on the total weight of the pulp slurry (unit: ppm)
Is.

<Water Repellency> The “water repellency” R defined in JIS P8137 was measured.

<Sliding Angle> A sliding angle in the vertical direction of the paper at 20 ° C. was measured by a sliding inclination angle measuring device specified in JIS P8147. The unit of display is (degrees).

<Abrasion resistance> According to JIS P8136, measurement was made in the horizontal direction of the paper. The unit of display is (times).

<Amount of residue adhering> This test is conducted by a table test. The same coating solution as in the example is applied to the same base paper as in the example with a Meyer bar. The coating amount should be 1.0 g / m ^{2 in} terms of wax solid content, 15 seconds after coating, put the aluminum foil, put it in a dryer at 140 ° C for 60 seconds, let it air-dry, and then cool it to room temperature. Peel off and measure the dry solid weight of the coating adhered to the aluminum foil. (The unit is mg / m ² ) In this test, when the measured weight is 200 mg / m ² or more, it tends to adhere to the dryer roll of the paper machine.

[0028]

[Table 1]

Continuation of front page (56) Reference JP-A-52-64305 (JP, A) JP-A-62-263279 (JP, A) JP-A-5-156208 (JP, A) JP-A-5-33295 (JP , A) JP-A-7-26495 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) D21H 11/00-27/42 C09D 101/00-201/10

Claims (3)

(57) [Claims] 1. A mixture of wax, water-soluble polymer and silicone oil, wherein the ratio of wax: water-soluble polymer is 90:10 to 30:70, and the ratio of silicone oil to wax is 0. Wax coated paper obtained by coating and drying a mixture of 3 to 5% by weight. 2. The wax-coated paper according to claim 1, wherein the water-soluble polymer substance is polyvinyl alcohol. 3. The wax coating according to claim 1, wherein an aqueous liquid containing wax, a water-soluble polymer substance and silicone oil is applied to the surface of the paper and dried. A method of manufacturing craft paper.