JP2018016902A - Water repellent for paper, and method for producing paper - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a water repellent for paper that can achieve both of high water repellency and low ink contamination.SOLUTION: A water repellent for paper contains a polymer containing a vinyl monomer with a long-chain alkyl group as a polymerization component, where the long-chain alkyl group of the vinyl monomer has 14 or more carbon atoms.SELECTED DRAWING: None

Description

  The present invention relates to a water repellent for paper and a method for producing paper.

  Paper such as wrapping paper and paperboard such as cardboard are subjected to a water-repellent treatment with a paper water repellent for the purpose of maintaining the quality of the contents during transportation, safe transport, and preventing strength deterioration due to moisture. (Patent Document 1 etc.).

JP2011-117107A

  In recent years, the composition of paperboard raw materials has changed, and the proportion of used paper with a high filler and fine fiber content has increased. Accordingly, the surface properties of the paperboard change, and even if a water repellent is applied to a paperboard having a high ratio of used paper, it is not possible to obtain a sufficient water repellent effect.

  Specifically, for example, in the production of corrugated cardboard, the water repellent melts due to the drying process immediately after the application of the water repellent and the heat when the core base paper is bonded to the paperboard coated with the water repellent, When this penetrates into the gaps between the pulp fibers, the water repellency decreases. And the paperboard with a larger amount of waste paper tends to lower the water repellency.

  In addition, when printing is performed on a paper board treated with a water repellent, if the amount of water repellent treatment is too large (water repellency is too strong), water-based ink may be repelled. The water-based ink that has not been instantaneously divided into the paperboard adheres to portions and equipment other than the printing location, and eventually becomes a stain on the printing surface, which may cause printing defects. On the other hand, the water repellent treatment amount is reduced to improve the permeability of the water-based ink and improve the printing defect, but naturally the water repellency is lowered.

  Therefore, an object of the present invention is to provide a water repellent for paper that can achieve both high water repellency and low ink contamination, and a method for producing paper using the same.

  In order to achieve the above object, the water repellent for paper of the present invention contains a polymer containing a vinyl monomer having a long-chain alkyl group as a polymerization component, and the length of the vinyl monomer is long. The chain alkyl group has 14 or more carbon atoms.

  The paper production method of the present invention is characterized in that the surface of the paper is subjected to a water repellent treatment with the paper water repellent of the present invention.

  According to the present invention, it is possible to provide a water repellent for paper that can achieve both high water repellency and low ink contamination, and a method for producing paper using the same.

  Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited by the following description.

  The present inventors emulsified a polymer mainly composed of a vinyl monomer having a long-chain alkyl group in the side chain as a polymer-type water-repellent component, and processed the water-repellent treatment with the obtained water-repellent agent. Focusing on the point that the water repellency is hardly lowered even when the paper is stored in a high temperature environment for a long time, the present invention has been achieved. Since the water repellent for paper of the present invention is excellent in water repellency, for example, high water repellency can be obtained even with a low processing amount. For this reason, for example, it is possible to achieve both improvement in stains on the printing surface during the printing process and heat and water repellency.

  The constituent ratio of the vinyl monomer having a long-chain alkyl group is, for example, 80 to 100% by weight or 90 to 100% by weight with respect to the total amount of monomer units constituting the polymer.

  The vinyl monomer having a long-chain alkyl group includes, for example, at least one of acrylate and methacrylate. The acrylate and methacrylate are preferably main components of the vinyl monomer. The “principal component” includes, for example, 50 wt% or more, 60 wt% or more, 70 wt% or more, 80 wt% or more, or 90 wt% or more, based on the total amount of the vinyl monomer. It means that it is at least wt%.

  In the paper manufacturing method of the present invention, for example, the surface after the water-repellent treatment may be printed.

  In the paper manufacturing method of the present invention, for example, the paper may be paperboard.

[1. Water repellent for paper]
Next, examples of the components of the water repellent for paper of the present invention will be described.

(1) Water-repellent polymer The water-repellent agent for paper of the present invention, as described above, contains a vinyl monomer having a long-chain alkyl group as a polymerization component, and a vinyl-based monomer having the long-chain alkyl group. It contains a polymer having 14 or more carbon atoms in the alkyl group (hereinafter sometimes referred to as “water-repellent polymer”). The vinyl monomer is preferably a main polymerization component of the water-repellent polymer. In the present invention, the “polymerization component” of the polymer is a monomer unit of the polymer, and the “main polymerization component” is, for example, 50% by weight based on the total amount of the monomer units constituting the polymer. These are monomer units that are 60% by weight or more, 70% by weight or more, 80% by weight or more, or 90% by weight or more. Examples of the vinyl monomer having a long chain alkyl group include vinyl monomers represented by the following chemical formula (1) or (2).

In the chemical formulas (1) and (2), X is H or CH ₃ . R ₁ and R ₂ are each a linear or branched alkyl group having 14 to 24 carbon atoms, and preferably a linear alkyl group having 14 to 24 carbon atoms.

In the chemical formula (1), the monomer in which X = H and R ₁ is C ₁₈ H ₃₇ (straight chain, stearyl group) represents stearyl acrylate.

In the chemical formula (1), a monomer in which X = CH ₃ and R ₁ is C ₁₈ H ₃₇ (straight chain, stearyl group) represents stearyl methacrylate.

In the chemical formula (2), the monomer in which X = H and R ₂ is C ₁₅ H ₃₁ (linear, pentadecyl group) represents vinyl palmitate.

  When the vinyl monomer is not blended or when the carbon number of the alkyl group of the vinyl monomer is shorter than 14, the water repellency of the water repellent using the polymer is lowered. Although the upper limit of carbon number of the alkyl group of the vinyl monomer is not particularly limited, it is, for example, 24 or less. Moreover, as for carbon number of the alkyl group of the said vinyl-type monomer, 14-22 are more preferable.

  In the water-repellent agent for paper of the present invention, the water-repellent polymer may be a homopolymer composed only of a vinyl monomer having a long-chain alkyl group (the alkyl group has 14 or more carbon atoms), or other monomer. A copolymer (copolymer) may be used. In the case of a copolymer, it may be a block copolymer or a random copolymer. The other monomer is not particularly limited. As described above, the constituent ratio of the vinyl monomer having a long-chain alkyl group is 80 to 100% by weight or 90 to 100% by weight with respect to the total amount of monomer units constituting the water-repellent polymer. Is preferable from the viewpoint of water repellency.

  Moreover, the manufacturing method of the said water repellent polymer is not specifically limited, For example, it can manufacture (synthesize | combine) by a well-known polymerization method.

(2) Other components The water repellent for paper of the present invention may or may not contain other components than the water repellent polymer as appropriate. Although the said other component is not specifically limited, For example, it is as follows.

  The other component may contain water, for example. The paper water repellent of the present invention may be, for example, in a state where the water repellent polymer is dispersed (emulsified) in water. Although the content rate of the said water is not specifically limited, For example, it is 50 weight% or more with respect to the total weight of the water repellent for paper of this invention, for example, 80 weight% or less.

  The other component may include, for example, paraffin (paraffin wax). By blending paraffin, for example, the emulsion stability is further improved. Although it does not specifically limit as said paraffin (paraffin wax), For example, normal paraffin, isoparaffin, cycloparaffin, oxidized paraffin, etc. are mentioned. In addition to or in place of the paraffin (paraffin wax), other waxes may be used. Examples of the other waxes include natural waxes such as carnauba wax, candelilla wax, montan wax, ceresin, and microcrystalline wax, and long chain alkyl esters such as beef tallow oil, stearyl stearate, pentaerythritol tetrastearate, and the like. Is mentioned. These waxes may be used alone or in combination. The amount of the wax used is not particularly limited, but the weight of the water repellent polymer is, for example, 30% by weight or more, or 50% by weight or more based on the total weight of the water repellent polymer and the wax. , 100% by weight or less, or 90% by weight or less.

  The other component may contain, for example, petroleum resin. By including the petroleum resin, for example, the water repellency and the emulsion stability of the water repellent for paper are further improved. In the present invention, the petroleum resin is, for example, an aliphatic petroleum resin, an aromatic petroleum resin, an alicyclic petroleum resin, or a mixed petroleum resin thereof and a resin component thereof containing maleic acid, maleic anhydride, Examples thereof include resins anion-modified with dibasic acids such as fumaric acid and itaconic acid. Examples of the aliphatic petroleum resin include petroleum resins obtained from butene, isobutene, pentene, pentadiene, isopropylene and the like. Examples of the aromatic petroleum resin include petroleum resins obtained from indene, methylindene, vinyltoluene, styrene, α-methylstyrene, β-methylstyrene, coumarone-indene and the like. Examples of the alicyclic petroleum resin include petroleum resins obtained from monomers such as cyclopentadiene and dicyclopentadiene. In the present invention, examples of the petroleum resin include rosin resins (gum rosin, rosin ester, rosin derivative), terpene resins, and the like. Examples of the rosin resins include rosins such as gum rosin, wood rosin or tall oil rosin, and resins obtained by anion modification with dibasic acids such as maleic acid, maleic anhydride, fumaric acid, itaconic acid, rosin esters, Examples include hydrogenated rosin and hydrogenated rosin ester. Examples of the terpene resin include α-pinene resin, β-pinene resin, and aromatic modified terpene resin obtained by copolymerizing terpenes such as α-pinene and β-pinene and aromatic monomers such as styrene. Etc. These petroleum resins may be used alone or in combination. The amount of the petroleum resin used is not particularly limited, but the weight of the petroleum resin is, for example, 50% by weight or more, or 60% by weight or more based on the total weight of the water-repellent polymer, the wax, and the petroleum resin. For example, it is 85% by weight or less, or 80% by weight or less.

  The other component may contain a fatty acid, for example. By including the fatty acid, for example, the effect that the salt of the fatty acid acts as an emulsifier and contributes to the improvement of the emulsion stability is obtained. Although it does not specifically limit as a fatty acid, For example, lauric acid, myristic acid, palmitic acid, a stearic acid, an oleic acid, a linoleic acid, a linolenic acid etc. are mentioned, You may use only 1 type or may use multiple types together. The amount of the fatty acid used is not particularly limited, but is, for example, 0% by weight or more, or 5% by weight or more, for example, 25% by weight or less, or 15% by weight or less, based on the weight of the water-repellent polymer. .

  The other component may contain an emulsifier, for example. Although it does not specifically limit as an emulsifier, For example, a nonionic surfactant and an anionic surfactant are mentioned, For example, only 1 type may be used or multiple types may be used together. Examples of the nonionic surfactant include POE alkyl ether types such as polyoxyethylene (POE) stearyl ether and POE oleyl ether, and POE fatty acid ester types such as POE monostearate and POE sorbitan monolaurate. Can be mentioned. Examples of the anionic surfactant include a carboxylate type, a sulfate type, a sulfonate type, and a phosphate type. The amount of the emulsifier used is not particularly limited, but is, for example, 0% by weight or more, or 15% by weight or more, for example, 60% by weight or less, 45% by weight with respect to the weight of the water-repellent polymer. It is as follows.

  The other component may contain a base, for example. By including a base, for example, the effect that the base forms a salt with the fatty acid and acts as an emulsifier can be obtained. The base may be an inorganic base or an organic base, and may be used alone or in combination. Examples of the inorganic base include alkali metal hydroxides such as sodium hydroxide and potassium hydroxide. Examples of the organic base include alkanolamines such as triethanolamine, diethanolamine, and monoethanolamine, morpholine, and amino alcohol.

  Although the manufacturing method of the water repellent for paper of this invention is not specifically limited, For example, it can manufacture by mixing and emulsifying all the said each component.

[2. Water repellent treated paper]
As described above, the paper production method of the present invention is characterized in that the surface of the paper is subjected to a water repellent treatment with the water repellent for paper of the present invention. As a result, the paper of the present invention can be produced in which the surface is subjected to a water-repellent treatment with the water repellent for paper of the present invention. In addition, as described above, the paper manufacturing method of the present invention may, for example, print on the surface after the water repellent treatment. In this way, it is possible to manufacture a paper printed on the surface after the water repellent treatment.

  In the present invention, “paper” may be paperboard as described above. In the present invention, “paperboard” refers to thick paper. The thick paper may be, for example, paper formed by laminating a plurality of papers. In the present invention, “paper” is not particularly limited, and examples thereof include wrapping paper, newspaper, books / magazines, and copy paper. In the present invention, the “paperboard” is not particularly limited, and examples thereof include cardboard, paper boxes / paper containers, base paper for building materials, and the like.

  The application of the water repellent for paper of the present invention is not particularly limited, and any paper may be used. However, according to the water repellent for paper of the present invention, it is possible to achieve both high water repellency and low ink contamination as described above. Therefore, the water repellent for paper of the present invention is particularly suitable for water repellent processing before printing on paper on which printing is performed.

The method of the water repellent treatment is not particularly limited. For example, the water repellent for paper of the present invention may be applied to the surface of paper or paperboard and dried. The amount of the water-repellent agent for paper of the present invention applied to the surface of the paper or paperboard is not particularly limited, but is, for example, 0.05 g / m ² in terms of the solid content in the water-repellent agent for paper. Above or 0.2 g / m ² or more, for example, 3 g / m ² or less, or 1.5 g / m ² or less. The “solid content” in the paper water repellent of the present invention refers to, for example, all components obtained by removing water from the paper water repellent of the present invention. Although a drying temperature is not specifically limited, For example, it is 80-160 degreeC or 100-140 degreeC, and a drying time is not specifically limited, For example, it is 10 seconds-10 minutes, or 30 seconds-5 minutes. The printing method is not particularly limited, and for example, general flexographic printing, offset printing, or gravure printing may be used, but flexographic printing is particularly preferable.

  Next, examples of the present invention will be described. However, the present invention is not limited to the following examples.

1. Water repellent production method (1) Water repellent polymer polymerization method (solution polymerization)
Synthesis example 1
A flask equipped with a stirrer, a condenser tube, a nitrogen inlet tube and a thermometer was charged with 100 parts by weight of behenyl acrylate and 100 parts by weight of toluene. After sufficiently replacing oxygen in the reaction system with nitrogen, the mixture was heated to 70 ° C., and 0.3 parts by weight of radical polymerization initiator AIBN dissolved in a small amount of toluene was charged into the reaction vessel. Next, the polymerization reaction was allowed to proceed for 8 hours in the temperature range of 75 to 80 ° C. After completion of the reaction, the mixture was cooled to room temperature to obtain a polymer A that was a water-repellent polymer.

Synthesis examples 2 to 10
Except having changed the monomer to be used into the monomer kind and ratio shown in following Table 1, it prepared by the method similar to the synthesis example 1, and obtained the polymer BJ which is a water repellent polymer as a polymer, respectively.

(2) Measurement of molecular weight of polymer For polymers A to J obtained in Synthesis Examples 1 to 10, the weight average molecular weight was determined using Waters analysis module Waters e2695, detector Waters 2414, and data processing Empower2 software (trade name). Measured.

(3) Method for producing water repellent, Example 1
9 parts by weight of the polymer A from which the solvent component has been removed by heating, 2 parts by weight of paraffin wax (trade name “Parvan 1320”, manufactured by ExxonMobil Co., Ltd.), petroleum resin (trade name “Quinton D-200”, Nippon Zeon Co., Ltd.) 13 parts by weight manufactured by the company, 19 parts by weight of the trade name “Haritac 4740”, 6 parts by weight of Harima Chemicals Co., Ltd., 0.6 parts of mixed fatty acid (trade name “Tsubaki Fatty Acid”, manufactured by Tsukino Food Industries, Ltd.), emulsifier (Trade name “Brownon SR-706” POE stearyl ether (EO = 6 mol), manufactured by Aoki Oil & Fat Co., Ltd.) 2.0 parts, 1.3 parts by weight of 48% aqueous potassium hydroxide, 1.3 weights of triethanolamine The parts were mixed and heated to 90-95 ° C. and mixed uniformly. Next, 64.8 parts by weight of warm water boiled in advance is gradually added at a flow rate of 3 g / min and phase inversion emulsification is carried out for 20 minutes, and then cooled to room temperature to give a water repellent (water repellent composition). Obtained.

Examples 2-9
A water repellent composition was obtained by emulsification in the same manner as in Example 1 except that the polymers B to H were used in place of the polymer A.

Example 10
A water repellent composition was obtained by emulsifying in the same manner as in Example 1 except that 11 parts by weight of polymer C was used instead of polymer A and paraffin wax.

Comparative example 1
A water repellent composition was obtained by emulsification in the same manner as in Example 1 except that 11 parts by weight of paraffin wax was used without using a polymer.

Comparative example 2
A water repellent composition was obtained by emulsification in the same manner as in Example 1 except that the polymer J was used instead of the polymer A.

-Examples 11-13
A water repellent composition was obtained by emulsification in the same manner as in Example 4 except that the blending amounts of polymer D and paraffin were changed.

Examples 14 to 15
A water repellent composition was obtained by emulsification in the same manner as in Example 4 except that the blending amounts of polymer D, paraffin and petroleum resin were changed.

2. Ink contamination evaluation (1) Preparation method of test piece treated with water repellent agent Water repellent treatment amount is 0.2 g / m ² (= weight of water repellent solid content per unit area of liner) A water repellent was applied to a liner (corrugated cardboard) having a basis weight of 280 g / m ^{2 with} a glass rod, and then dried at 120 ° C. for 1 minute in a circulation dryer to obtain a water repellent liner (paper of the present invention).

(2) Evaluation Method of Ink Contamination Property An 87.5% aqueous solution of black water-based flexographic ink (trade name “FK-Flemio DF-260 black”, manufactured by Sakata Inx Co., Ltd.) was added to the above water-repellent treatment test piece. After coating with No. 12, the white coated paper was bonded to the ink coated surface after 10 seconds and pressed with a load of 5 kg, and the ink stain on the white coated paper surface when peeled off from the test piece was visually confirmed. As a result of the evaluation, a three-step evaluation of ◯ Δ × was performed as follows.

○: Equivalent to ink stains on a test piece not treated with water repellent treatment (no ink stains)
Δ: Dirty than the ink smudged state on the test piece not treated with water repellent finish ×: Remarkably smudged than the ink smudged state on the test piece not treated with water repellent finish

3. Water repellent evaluation (1) Method for producing water repellent paper After applying a water repellent to a liner having a basis weight of 280 g / m ^{2 with} a glass rod so that the water repellent treatment amount is 0.2 g / m ² , Water-repellent paper was obtained by drying in a circulating dryer at 120 ° C. for 1 minute.

(2) Evaluation method of water repellency The water repellent paper produced by the above method was heat-treated in a circulation dryer set at 160 ° C. for 30 minutes, and then subjected to a water repellency evaluation test. This is to reproduce the state when the water repellent treated water repellent liner is industrially mass-produced, because heat is easily trapped inside the roll when it is wound and stored. After the heat treatment, JAPAN TAPPI paper pulp test method no. 68: 2000, the water repellency was measured in accordance with the method specified. Specifically, the water-repellent paper prepared by the above method was inclined at 45 °, and ion-exchanged water was dropped from a position 10 mm apart in the vertical direction (1 drop: about 0.1 ml), and the trace of the flow was observed. . The water repellency was evaluated by R0 to R10 according to the evaluation criteria shown in Table 2 below. The water repellency with the smallest number after R (eg, R0) has the lowest water repellency, and the water repellency with the largest number after R (eg, R10) has the highest water repellency. R7 or more is good water repellency.

  Tables 3 to 7 below show the compositions of the water repellents (water repellent compositions) of Examples 1 to 15 and Comparative Examples 1 and 2, together with the ink stain resistance and water repellency evaluation results.

  As shown in Tables 3 to 7, in all of Examples 1 to 15, the water repellency was in the range of R7 to R10, the ink contamination was ◯, and good results were obtained in all cases. Regarding water repellency, as described above, despite the heat treatment at a high temperature of 160 ° C. for 30 minutes, the water repellent coating film had high heat resistance, and thus high water repellency was obtained. On the other hand, Comparative Examples 1 and 2 were both inferior to the Examples in terms of water repellency, R6 or R6-7, and the ink staining property was Δ and poor.

  Table 5 shows the results of examples (Example 3, Example 9, and Comparative Example 1) in which the composition ratio of the water-repellent polymer and paraffin was changed. As shown in the table, Example 3, Example 10, and Comparative Example 1 have the same composition except that the amounts of water-repellent polymer (Polymer C) and paraffin used are different (parts by weight). As shown in the table, Example 3 in which 2.0 parts by weight of paraffin was added and Example 10 in which no paraffin was added similarly achieved both high water repellency and low ink contamination. On the other hand, in Comparative Example 1 in which 11.0 parts by weight of paraffin was added and no water-repellent polymer was added, the water repellency was poor with R6 and the ink contamination was poor with Δ. Further, in Comparative Example 2, the monomer (lauryl acrylate) constituting the polymer J has as few as 12 alkyl carbon atoms, and as described above, the water repellency is inferior to R6-7 and the examples, and the ink stain resistance. Was also bad.

  Table 6 shows another example (Examples 4, 11, 12 and 13) in which the composition ratio of the water repellent polymer and the paraffin was changed. As shown in the table, Examples 4, 11, 12, and 13 have the same composition except that the amount of water-repellent polymer (Polymer D) and paraffin used (parts by weight) are different. As shown in the table, good water repellency was obtained in all the examples, but the polymer / (polymer + paraffin) ratio (weight ratio of the water-repellent polymer to the total weight of the water-repellent polymer and the paraffin wax) was high. The higher water repellency was obtained.

  Table 7 shows an example in which the ratio of petroleum resin / (petroleum resin + polymer + paraffin) (weight ratio of petroleum resin to the total weight of water repellent polymer, paraffin wax and petroleum resin) was changed (Examples 14 and 4). And 15). As shown in the table, Examples 14, 4 and 15 have the same composition except that the amounts of water-repellent polymer (Polymer D) and petroleum resin used are different (parts by weight). As shown in the table, good water repellency was obtained in any of the examples, but the higher the ratio of petroleum resin / (petroleum resin + polymer + paraffin), the higher the water repellency. The reason for this is not clear, but it is assumed that the emulsion stability was further improved. As shown in Tables 4 and 5, when the water-repellent polymer was not added (Comparative Example 1), the water repellency was inferior.

  In addition, as shown in Table 3 above, in the monomer constituting the water repellent polymer, Example 2 using a linear C18 acrylate homopolymer and Example 3 using a branched C18 acrylate are both similarly repellent. It was confirmed that the water level was extremely high.

Claims (6)

For paper, comprising a polymer containing a vinyl monomer having a long chain alkyl group as a polymerization component, and wherein the long chain alkyl group of the vinyl monomer has 14 or more carbon atoms Water repellent. The water repellent for paper according to claim 1, wherein a constituent ratio of the vinyl monomer in the polymer is 80 to 100% by weight with respect to a total amount of monomer units constituting the polymer. The water repellent for paper according to claim 1, wherein the vinyl monomer contains at least one of acrylate and methacrylate. A method for producing a water-repellent-treated paper, characterized in that the surface of the paper is subjected to a water-repellent treatment with the water-repellent agent for paper according to any one of claims 1 to 3. Furthermore, it prints on the surface after the said water-repellent processing, The manufacturing method of Claim 4 characterized by the above-mentioned. The manufacturing method according to claim 4 or 5, wherein the paper is paperboard.