JPH01192898A - Reinforcing material for paper - Google Patents

Abstract

PURPOSE:To obtain a reinforcing material strengthening of resistances to water and oils and dimensional stabilities, comprising a mixture of PVA-based synthetic resin and soluble zirconium compound. CONSTITUTION:The aimed reinforcing material consisting of a mixture of (A) a PVA base synthetic resin and (B) a soluble zirconium compound {e,g., zirconyl nitrate [Zr(NO3)2.2H2O]}. The mixing ratio is preferably 0.5-20 pts.wt. calculated as ZrO2 of the component B based on 100 pts.wt. the component A.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a reinforcing agent that enhances the water and oil resistance and dimensional stability of paper.

[Conventional technology]

Conventionally, polyvinyl alcohol has been used as a reinforcing agent for this type of paper.

[Problem that the invention seeks to solve]

However, polyvinyl alcohol is water-soluble and has problems particularly in water resistance and dimensional stability at high humidity.

[Means for solving problems]

The present invention provides a paper reinforcing agent made of a mixture of a polyvinyl alcohol-based synthetic resin and a soluble zirconium compound as a means to solve the above-mentioned conventional problems.

<Strengthening agent> The reinforcing agent of the present invention is a mixed solution of a polyvinyl alcohol-based synthetic resin and a soluble zirconium compound.

The above-mentioned polyvinyl alcohol-based synthetic resins include polyvinyl alcohol with various degrees of saponification and polymerization, or copolymers of vinyl acetate and monomers copolymerizable with vinyl acetate, such as allyl alcohol, isopropenyl alcohol, and vinyl ethers. Saponified products, or modified polyvinyl alcohols obtained by modifying the above-mentioned polyvinyl alcohols with formaldehyde or the like are included.

Examples of the above-mentioned soluble zirconium compounds include compounds that are water-soluble or become water-soluble with acid, such as zirconium halides such as zirconium oxychloride, hydroxyzirconium chloride, zirconium tetrachloride, and zirconium bromide, zirconium sulfate, basic zirconium sulfate, Examples include zirconium salts of mineral acids such as zirconium nitrate, zirconium salts of organic acids such as zirconyl acetate and zirconyl formate, zirconium complex salts such as ammonium zirconium carbonate, sodium zirconium sulfate, ammonium zirconium acetate, sodium zirconium oxalate, and ammonium zirconium citrate. be done. Among these compounds, zirconium oxychloride, zirconium sulfate, and zirconium nitrate are more preferred.

The polyvinyl alcohol synthetic resin and the soluble zirconium compound are preferably mixed in an amount of 0.05 to 35 parts by weight based on ZrO2 based on 100 parts by weight of the polyvinyl alcohol synthetic resin, More preferably, the soluble zirconium compound is mixed as ZrO2 in a ratio of 0.5 to 20 parts by weight with respect to 100 parts by weight of the polyvinyl alcohol synthetic resin.

The above mixture is provided as a solution, and the solvent used is water or an organic solvent compatible with water such as methanol, ethanol, acetone, dioxane, etc.

The above mixture is usually provided as a solution with a concentration of 1 to 30% by weight.

<Strengthening method> To strengthen paper using the reinforcing agent of the present invention, there are methods of coating paper with the reinforcing agent, immersing paper in the reinforcing agent, and making paper by mixing the reinforcing agent with pulp. etc.

In either case, it is ultimately necessary to bring the reinforcing agent into an alkaline state for curing. To make the reinforcing agent alkaline, a latent alkali that decomposes to produce an alkali, such as sodium formate, potassium formate, sodium acetate, potassium acetate, ammonium acetate, or ammonium formate, is mixed in advance with the reinforcing agent of the present invention and applied to the paper. Alternatively, there is a method in which the reinforcing agent is impregnated or mixed with pulp, or a method in which the reinforcing agent is applied or impregnated onto paper without making it alkaline, or mixed into pulp, and the resulting paper is brought into contact with an alkali.

In the former case, when the treated paper is dried, it becomes alkaline and the reinforcing agent hardens; in the latter case, the reinforcing agent hardens when the treated paper is brought into contact with an alkali.

<Other components> Polyvinyl alcohol, polyethylene glycol, polypropylene glycol, and ethylene glycol may be added to the above-mentioned reinforcing agent of the present invention.

Propylene glycol, starch, modified starch, carboxymethyl cellulose, gelatin, surfactant.

Mineral oil, animal and vegetable oil, modified mineral oil, modified animal and vegetable oil.

Antibacterial and antifungal agent, fragrance + PH regulator, rosin, polyacrylamide, acrylic resin emulsion, synthetic rubber latex, phenolic resin, urea resin.

Sizing agents such as melamine resin, urethane resin, epoxy resin, alkyl ketene dimer, alkyl kenyl or alkyl succinic anhydride, size fixing agent, antifoaming agent, pigments such as clay, kaolin, calcium carbonate, barium sulfate, titanium oxide, etc., and dyes. .

Other ingredients such as fluorescent bleaches may also be added.

[Effect]

The soluble zirconium compound, which is a component of the reinforcing agent of the present invention, becomes a zirconium ion with a maximum coordination number of 8 in an aqueous solution, and forms a stable complex with the hydroxyl group contained in the polyvinyl alcohol synthetic resin.

In an alkaline state, zirconium acts as a crosslinking agent for polyvinyl alcohol-based synthetic resin, forming a two-dimensional structure. The above-mentioned three-dimensional polyvinyl alcohol synthetic resin is extremely tough and has water resistance, oil resistance, solvent resistance, and heat resistance.

〔Effect of the invention〕

Therefore, paper reinforced with the reinforcing agent of the present invention has a high degree of water and oil resistance, and also exhibits excellent dimensional stability even at high temperatures and/or high humidity. Paper strengthened by this method is extremely useful for information industry papers such as electronic copy paper and microcapsule copy paper.

Example 1 [Preparation of reinforcing agent A] Zirconyl nitrate (ZrO(NO3), -2H20, crystal) containing 35% by weight of ZrO in 100 g of polyvinyl alcohol with a degree of polymerization of 1500 and a degree of saponification of 98.8 mol%.
10K was added and dry mixed in a mortar, and water was added and dissolved by heating to prepare 1000 g of mixed solution A.

6- Add the same type of polyvinyl alcohol 10 to the above mixed solution A.
Strengthening agent A was obtained by adding 1000 g of a wt% aqueous solution and 30 g of ammonium acetate.

Example 2 [Preparation of reinforcing agent B] Zr was added to 800 g of a 12.5% by weight aqueous solution of polyvinyl alcohol with a degree of polymerization of 1700 and a degree of saponification of 98.9 mol%.
Zirconyl nitrate (ZrO(
Mixed solution B was prepared by adding 16 g of NO3) 2.2H20) and further adding water to make the total amount 1250 g.

Strengthening agent B is obtained by adding 2 g of funnel oil to the above mixed solution B.
I got it.

Example 3 [Preparation of Strengthening Agent C] 200 g of a 10% by weight aqueous polyacrylamide solution was further added to the mixed solution A of Example 1 to obtain a strengthening agent C.

Example 4 [Manufacture of test paper] Pulp slurry (L-BKP, freeness 300 ml csf) with a concentration of 2% by weight was mixed with reinforced rosin as a sizing agent, 0.5% by weight in terms of solid content, and sulfuric acid based on the pulp solid content. The bands were added in order of 2% by weight, and water was further added to dilute the slurry solids concentration to 1% by weight. Next, the sample was pressed using an automatic press machine at 8 kg/cd for 7 minutes, and then dried using a rotary dryer at 120°C for 14 minutes to obtain a test paper.

Example 5 [Manufacture of processed paper A] Reinforcing agent A was applied to one side of the test paper obtained in Example 4 in an amount of 20 g/po using a coil coater, and heated and dried at 120°C for 5 minutes to produce processed paper A. Manufacture.

Example 6 [Manufacture of processed paper B] The test paper obtained in Example 4 was immersed in a tank filled with reinforcing agent B to impregnate it in an amount of 30 g/n, and then a 1% by weight aqueous sodium carbonate solution was added to both sides. After spraying, heat drying is performed at 130° C. for 5 minutes to produce processed paper B.

Example 7 [Manufacture of processed paper C] In Example 4, 1% by weight of reinforcing agent C and 0.03% by weight of sodium formate were further added before adding reinforced rosin and bisulfuric acid band, and then processed paper C was produced in the same manner. Manufacture.

Comparative Example 1 [Manufacture of processed paper] 18 = 20 g/rd of a 10 wt% aqueous solution of polyvinyl alcohol with a degree of polymerization of 1500 and a degree of saponification of 98.9 mol% was added to one side of the test paper obtained in Example 4. It is coated with a coil coater and dried by heating at 120° C. for 5 minutes to produce processed paper.

Comparative Example 2 [Production of processed paper E] The test paper obtained in Example 4 was prepared with a degree of polymerization of 1700 and a degree of saponification of 98.
．． Processed paper was immersed in a tank filled with a reinforcing agent made by adding 2 g of funnel oil to a 10 wt. Manufacture E.

Comparative Example 3 [Manufacture of processed paper F] In Example 4, the degree of polymerization was further increased to 1500 and the degree of saponification was 98.
．． 9 mol% polyvinyl alcohol 10% by weight aqueous solution 2
000 g of polyacrylamide 10% by weight aqueous solution
1% by weight of the reinforcing agent prepared by adding 00 g of the reinforcing agent was added before adding the reinforcing rosin and the double sulfuric acid band, and then processed paper F was produced in the same manner.

Processed papers A, B, and C produced as described above.

Dimensional stability, water resistance, and oil resistance were measured for D, E, and F.

1. Dimensional stability A test piece (15 x 250 m) of the above processed paper was heated at 25°C for 6
The dimensions are measured after being left for 24 hours under 0% RH conditions (standard conditions). Next, the processed paper was heated at 25°C and 80% RH.
(high humidity condition) and 25° C. and 35% RH (low humidity condition) for 24 hours, and then the dimensions are measured.

Table 1 shows the results of calculating the dimensions when left under high temperature conditions and low humidity conditions, with the dimensions when left under standard conditions being 100.

Table 1 Processed paper A using the reinforcing agent of the present invention as shown in Table 1
, B, and C have smaller dimensional changes under high-humidity and low-humidity conditions than E and F, which are treated papers using conventional reinforcing agents (polyvinyl alcohol).

2. Water resistance After immersing a test piece (15 x 250 nwn) of the above processed paper in deionized water for 1 hour, it was tested with a span of 180 m and a load of 20
A tear test was conducted using a Tensilon tester under conditions of glare and a tensile speed of 30 cm/min, and the wet tear length was determined in accordance with a conventional method. For comparison, a similar test piece was tested at 25°C and 60% RH.
After leaving it for 24 hours, the standard tear length was determined in the same manner. The results are shown in Table 2.

Processed paper A using the reinforcing agent of the present invention as shown in Table 2
, B, and C exhibit larger values for both standard tear length and wet tear length than treated papers E and F, which use conventional reinforcing agents (polyvinyl alcohol).

3. Oil resistance After immersing a test piece (15 x 250 + nm) of the above processed paper in Kijiroll for 1 hour, 2. The oil immersion fracture length was determined in the same manner as the water resistance. Standard tear length is 2. The results obtained for water resistance are used. The results are shown in Table 3.

Processed paper A using the reinforcing agent of the present invention as shown in Table 3
, B, and C exhibit larger values of kijiroll immersion tearing length than processed papers E and F using conventional reinforcing agents (polyvinyl alcohol).

Claims (1)

[Claims] Paper reinforcing agent made of a mixture of polyvinyl alcohol synthetic resin and soluble zirconium compound