JPH01239194A - Production of paper - Google Patents

Abstract

PURPOSE:To reduce adhesion of adhesive, etc., and to produce paper free from troubles such as adhesion to wire, by treating pulp prepared by breaking old papers containing adhesive, etc., with an aqueous solution of modified PVA. CONSTITUTION:Pulp prepared by breaking old papers containing adhesive and tacky agent is treated with an aqueous solution of hydrophobic group-containing modified PVA (preferably modified PVA containing >=4C alkyl group at the end of molecule). The polymerization degree of the modified PVA is preferably 50-3,000. The concentration of the aqueous solution of the modified PVA is preferably 0.01-0.5%.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing paper, and more specifically, when manufacturing paper using waste paper containing an adhesive or adhesive, The present invention relates to an improved paper manufacturing method that prevents contamination of paper machines or paper.

B. Prior Art Conventionally, paper, particularly paperboard or cardboard base paper, has been manufactured using waste paper as one of the pulp raw materials for the purpose of effective resource utilization and reduction of product costs. As used paper, there are many things used, such as newspapers, magazines, paper boxes, labels coated with adhesive or adhesive, paper tubes, and mixtures thereof. Since waste paper contains more or less foreign matter, it has conventionally been disintegrated with a pulper and then used with a screen or cleaner to remove foreign matter.

However, in recent years, the usage ratio of waste paper has increased, and water-insoluble resins present in waste paper, especially hot melt adhesives,
With the increase in adhesives such as emulsion adhesives and gum,
Various problems have arisen.

For example, the above-mentioned adhesives are generally easily crushed and tend to pass through the screen and remain in the pulp slurry.
Problems arise due to accumulation, and further problems such as dryer roll stains occur during post-processing of the obtained paper.

To solve these problems, attempts have been made to reduce the stickiness by mixing pigments with pulp slurry and sprinkling it on the sticky material, or by immersing the core slurry in an aqueous solution of cellulose derivatives to reduce the stickiness. Although attempts have been made, the current situation is that almost no practical level of effectiveness has been achieved.

C. Problems to be Solved by Ming The purpose of the present invention is to solve the above-mentioned problems and to make it possible to use paper without causing the above-mentioned troubles even when using adhesives or waste paper containing adhesives. The purpose is to provide a manufacturing method.

03 Means for Solving the Problems The inventors of the present invention solved the above problems and made extensive studies to achieve the above objectives. By treating the pulp obtained by disintegrating it with an aqueous solution of modified polyvinyl alcohol having a hydrophobic group, the adhesion of the adhesive to wires, press rolls or dryer rolls will be significantly reduced, leading to problems. The present invention was completed based on the discovery that this decreases significantly.

The present invention will be explained in more detail below.

Various types of modified polyvinyl alcohol having a hydrophobic group (hereinafter polyvinyl alcohol will be abbreviated as PVA) used in the present invention can be used.
Modified PVA or PV having a long chain alkyl group or a halogenated alkyl group in the side chain or terminal
Examples include block copolymers of A and water-insoluble polymers.

Furthermore, modified PVA containing an ionic group in addition to the above-mentioned hydrophobic group can also be used.

The degree of polymerization of these modified PVAs is not particularly limited, but is usually selected from the range of 50 to 3,000, and the degree of saponification is usually selected from the range of 70 to 100 mol%.

There are no particular limitations on the method for producing the above-mentioned modified PVA. All conventionally known methods can be used, such as a method of saponifying a copolymer of a vinyl ester and a vinyl monomer containing a hydrophobic group, a chain transfer agent having a hydrophobic group, etc. A method for saponifying a polymer obtained by polymerizing a vinyl ester in the presence of PV
A method in which an aldehyde, acid, isonoanate, etc. having a hydrophobic group is introduced into A by a post-reaction, and in the presence of modified PVA having a diol group at the end, a hydrophobic compound such as vinyl ester, (meth)acrylic acid ester, styrene, etc. A method such as radical polymerization of monomers to produce a block copolymer with PVA can be used.

Among the above-mentioned modified PVA, modified PVA having an alkyl group having 4 or more carbon atoms at the end of the molecule is most preferably used from the viewpoint of preventing the adhesion of the adhesive.

In the present invention, adhesives present in waste paper include pot-melt adhesives such as copolymers of ethylene and vinyl acetate or polyester resins, adhesives such as rubber-based and acrylic resin-based adhesives, and adhesives made of various emulsions. , and tackifiers such as wax and pitch used together with these.

In the method of the present invention, it is necessary to disintegrate the waste paper containing the adhesive or pressure-sensitive adhesive described above, and then treat the resulting pulp with the aqueous solution of the hydrophobic group-modified PVA described above.

The concentration of the modified PVA aqueous solution used at this time is Q
, 001 to 5%, preferably 0.005 to 1%, more preferably 0.01 to 0.5%. 0.001
If it is less than 5%, the effect is low, and if it exceeds 5%, it is unfavorable in terms of workability, such as high viscosity and easy foaming.

Various methods can be adopted for treating the pulp obtained from waste paper with the modified PVA aqueous solution. A method of using an aqueous solution containing the modified PVA as the water of
Examples include a method of spraying an aqueous VA solution, but the method of Menja is preferably used. At that time, there is no problem in using a mixture of deinking agents, pigments, dyes, paper strength enhancers, size improvers, etc.

According to the method of the present invention, troubles when producing paper using adhesive or adhesive-containing waste paper are greatly reduced, and the resulting paper can be used to Troubles during processing are also greatly reduced.

Although the details of the reason why the above-mentioned remarkable effects are obtained are unknown, it is presumed as follows.

That is, the modified PV having a hydrophobic group used in the present invention
A easily adsorbs to the surface of the adhesive or pressure-sensitive adhesive and easily forms a film on that surface, so it significantly reduces the adhesion of the adhesive or pressure-sensitive adhesive and does not adhere to or accumulate on wires, press rolls, dryer rolls, etc. For,
It is estimated that the problem will be reduced to 1].

The present invention will be specifically explained below with reference to Examples, but the present invention is not limited thereto. Note that the middle part of the example indicates parts by weight.

Example 1 In order to clearly demonstrate that treating an adhesive with modified PVA having a hydrophobic group significantly reduces the adhesion of the adhesive, the following model test was conducted.

It has an alkyl group with 12 carbon atoms at the end, and the degree of polymerization is 3001.
0.0005 of modified PVA with saponification degree of 99.2 mol%
．． 0.001.0.01, o, i%, 1.0% aqueous solution was prepared, a polyester adhesive tape was immersed in the solution at 500C for 1 hour, and then adhered to a stainless steel plate preheated to 50℃. Bonding was carried out at 50° C. for 10 minutes under a load of .5 kg/affi'. The 180° peel adhesion strength of this adhesive tape was determined to be 300mm/300mm by autograph.
The measurement was performed at a tensile speed of min. The results are shown in Table 1.

Examples 2 to 5, Comparative Examples 1 to 4 The same procedure as in Example 1 was performed except that the modified PVA used in Example 1 was replaced with the following. The results are shown in Table 1.

Example 2: A 0.1% aqueous solution of modified PVA containing 0.2 mol% of alpha olefin having 14 carbon atoms, a degree of polymerization of 500, and a degree of saponification of 88 mol%.

Example 3: Vinyl ester of branched fatty acid having 10 carbon atoms 3
mol% and maleic anhydride 1 mol%, polymerization degree 30.
0.0.1% aqueous solution of modified PVA with saponification degree of 93 mol%.

Example 4: PVA with a degree of polymerization of 1700 and a degree of saponification of 98.5 mol % was acetalized and then modified by introducing 5 mol % of alkyl groups having 4 carbon atoms.
1% aqueous solution.

Example 5: P with a degree of polymerization of 500 and a degree of saponification of 98.5 mol%
Block copolymer of VA and polymethyl acrylate (PVA/polyacrylic acid) -1-ru 100/10 (weight ratio) 0.
1% aqueous solution.

Comparative Example 1 - Water only.

Comparative Example 2: 1% talc solution.

Comparative Example 3: P with a degree of polymerization of 550 and a degree of saponification of 98.5 mol%
01% aqueous solution of VA.

Comparative Example 4: 0.1% aqueous solution of methylcellulose.

Blank spaces below Examples 6 to 8 Ethylene/onyl acetate copolymer hot melt adhesive using modified PVA with the following number of carbon atoms at the end, a degree of polymerization of 500, and a degree of saponification of 98.5 mol% as an adhesive. 2 drugs
The adhesive force with the stainless steel board was measured in the same manner as in Example 1 using the paperboard to which 0 g/m' was attached.

The results are shown in East Table 2.

Table 2 Comparative Examples 5-6 Example 6 except that the following radish was used instead of modified PVA
same as? I went here. The results are shown in Table 2.

Comparative Example 5: Water Only Comparative Example 6: Hydroquinopropyl Methyl Cellulose Example 9 Waste paper containing an ethylene/vinyl acetate copolymer pot-melt adhesive was digested and washed in a papermaking test machine, and then processed in a beating machine. The modified PVA used in 1 was beaten in a 001% aqueous solution, and the resulting velves slurry was made into paper using a circular mesh paper machine and dried at 150°C using a hot roll. After this operation was performed continuously on 10 sheets of paper, the state of adhesion of the hot melt adhesive to the hot roll and the state of transfer of the adhesive to the surface of the obtained paper were observed. The results are shown in Table 3.

Comparative Examples 7-8 The same procedure as in Example 9 was carried out except that the following treatment liquid was used. The results are shown in Table 3.

Comparative example 7; water only 8: Methylcellulose Patent applicant RiRashi Co., Ltd.

Claims (2)

[Claims] (1) A paper manufacturing method characterized in that when paper is manufactured using waste paper containing an adhesive or adhesive, pulp obtained by disintegrating the waste paper is treated with an aqueous solution of modified polyvinyl alcohol having a hydrophobic group. . (2) The method for producing paper according to claim 1, wherein the modified polyvinyl alcohol having a hydrophobic group is a modified polyvinyl alcohol having an alkyl group having 4 or more carbon atoms at the end of the molecule.