JP2821897B2 - Surface sizing agent - Google Patents

Description

The present invention relates to a surface sizing agent. For more information,
The present invention relates to a surface sizing agent having good size effect and acid stability and low foaming property.

[Conventional technology]

Conventionally, aqueous solutions of styrene-maleic acid-based or α-olefin-maleic acid-based polymers have been known as surface sizing agents, but all of them are insufficient in size effect, low foaming property, and acid stability. . Therefore, when these surface sizing agents are applied to base paper, there is a disadvantage that foaming and operability decrease due to so-called gum-up occur.

[Problems to be solved by the invention]

The present inventors have focused on α-olefin-maleic acid-based polymer to solve the above problems, and as a result,
By using a specific α-olefin at a specific ratio in combination, it can be seen that the foaming property is much lower than that of a conventionally known surface sizing agent and an excellent sizing effect can be exhibited. Have surprisingly found that they are also excellent in acid stability and solubility in water. The present invention has been completed for the first time based on this fact.

[Means for solving the problem]

That is, the present invention relates to (a) an α, β-unsaturated polycarboxylic acid or its salt unit (component (a)) 30 to 70 mol% (b) 2,4,4-trimethyl-1-pentene ((b) (C) a linear α-olefin having 8 to 20 carbon atoms (component (c)) 60 to 5 mol%, and (b) / (c) is 8/2. A surface sizing agent comprising a water-soluble polymer having a composition ratio of 2 to 2/8 as an active ingredient; and (a) α, β-unsaturated polycarboxylic acid or a salt unit thereof ((a) component) 30 to 70 mol% (b) 2,4,4-trimethyl-1-pentene (component (b)) 5 to 60 mol% (c) linear α-olefin having 8 to 20 carbon atoms (component (c) ) 60 to 5 mol% and (d) another monomer unit (component (d)) 0 to 30 mol%, and (b) / (c) is a composition ratio of 8/2 to 2/8. Is a water-soluble polymer According to the surface sizing agent, characterized in that the active ingredient.

Among the α, β-unsaturated polycarboxylic acid or its salt unit (hereinafter, referred to as “component (a)”) which is a component of the surface sizing agent of the present invention, maleic acid,
Examples thereof include dicarboxylic acids such as fumaric acid, itaconic acid, and citraconic acid, and salts of the dicarboxylic acids. Preferred among the dicarboxylic acids are maleic acid and itaconic acid. Examples of the kind of the salt of the polycarboxylic acid include an alkali metal salt such as a sodium salt or a potassium salt, an ammonium salt, an aliphatic amine salt having 1 to 12 carbon atoms, and an alkanolamine salt. Of these salts, sodium salts, potassium salts and ammonium salts are preferred. These salts may be either completely neutralized salts or partially neutralized salts.

The component (b) which is a component of the surface sizing agent of the present invention is 2,4,4-trimethyl-1-pentene. Normally, diisobutylene, a dimer of isobutylene, is in the α form (2,
4,4-trimethyl-1-pentene) and β-form (2,4,4-
Trimethyl-2-pentene), but can be subjected to the polymerization of the present invention only with α-form 2,4,4
-Trimethyl-1-pentene only. However, it is possible to use commercially available diisobutylene as the above mixture, and in this case, the β-form may be distilled off after the completion of the polymerization.

8 to 20 carbon atoms which are constituents of the surface sizing agent of the present invention.
1-octene, 1-nonene, 1-decene, 1-octene,
Dodecene, 1-tetradecene, 1-pentadecene, 1-
Hexadecene, 1-octadecene, 1-eicosene and the like can be exemplified. Taking into account the performance of the obtained surface sizing agent, particularly the sizing effect, the stability of the aqueous solution of the sizing agent, etc., among these, a linear α-olefin having 9 to 14 carbon atoms is more preferable. A linear α-olefin having less than 8 carbon atoms tends to reduce the size effect, and a linear α-olefin having more than 20 carbon atoms decreases the solubility of the obtained surface sizing agent in water. Are not preferred. The reason why the branched-chain one is excluded is that foamability is larger than that of a linear α-olefin.

Other monomer units (hereinafter, referred to as component (d)) which are optional components of the surface sizing agent of the present invention include acrylic acid, methacrylic acid, acrylamide, methacrylamide, acrylonitrile, 2-hydroxyethyl methacrylate and the like. Water-soluble monomer, alkyl acrylate, alkyl methacrylate, styrene, α-methyl styrene,
Oil-soluble monomers such as vinyl acetate and glycidyl methacrylate are exemplified. These can be used without departing from the object of the present invention, and are usually preferably less than 30 mol% based on the total amount of monomers used.

In the present invention, the above various components are used in the following composition ratios.

The component (a) is usually about 30 to 70 mol%, preferably 40 to 60 mol%, in the polymer. (A) The composition ratio of the component is
If the amount is less than 30 mol%, the water-solubility of the resulting sizing agent is reduced, and if it exceeds 70 mol%, the sizing effect is undesirably reduced. The composition ratio of the component (b) is usually about 5 to 60 mol%, preferably 10 to 55 mol%. When the amount of the component (b) is less than 5 mol%, the sizing effect is reduced. When the amount exceeds 60 mol%, the sizing effect is reduced and foaming is increased, so that both are not preferred. The composition ratio of the component (c) is usually about 60 to 5 mol%,
Preferably it is 55 to 10 mol%. (C) component is 5 mol%
If the amount is less than 60 mol% or more, the size effect is reduced, which is not preferable.

Although the composition ratios of the component (a), the component (b) and the component (c) are as described above, the following conditions must be further satisfied. That is, the total amount of the components (b) and (c) used in the polymer is usually about 30 to 70 mol%, preferably 40 to 60 mol%, and the component (b) relative to the component (c). Is essential to be 8/2 to 2/8, preferably 7/3 to 3/7. When the total amount of the component (b) and the component (c) is less than 30 mol%, the size effect is reduced,
On the other hand, if it exceeds 70 mol%, the solubility in water is reduced, and neither is preferred. When the composition ratio of the component (b) to the component (c) is less than the lower limit ratio, the size effect is reduced. When the composition ratio exceeds the upper limit ratio, the size effect is reduced and foamability is increased. Are not preferred.

The composition ratio of the component (d) is usually 30 mol% or less, preferably 20 mol% or less in the polymer. If the amount of the component (d) exceeds 30 mol%, the size effect is undesirably reduced.

The degree of neutralization of all carboxyl groups in the polymer is appropriately determined in consideration of the water solubility of the obtained copolymer, but is usually 50%.
More preferably, it is preferably at least 60%. Adjustment of the degree of neutralization can be carried out in advance at the stage of the monomer, and can also be carried out after the production of the polymer. The amount of the half amide group in the polymer is not particularly limited, but from the viewpoint of solubility in water in the obtained polymer, 10 to 90 mol% of the component (a) forms a half amide. Is preferred. In particular, as a method for semi-amidating the component (a), a method in which ammonia or the like is used in advance for the monomer (a) as a monomer under a predetermined condition, or a copolymer containing a predetermined amount of the component (a) is used. Any method of causing ammonia or the like to act on the coalescence can be adopted. For example, as a specific example of the latter, a predetermined amount of ammonia, an aliphatic amine having 1 to 12 carbon atoms, an alkanolamine, or the like is added to the obtained copolymer, and the reaction temperature is 20 ° C or higher, preferably 30 to 100 ° C. ° C
The reaction may be carried out under the conditions of about 0.5 to 8 hours, preferably 0.5 to 3 hours.

The surface sizing agent of the present invention includes the various components ((a) to
It can be easily produced by copolymerizing the component (c) and, if necessary, the component (d)) in the presence of a suitable polymerization initiator. The polymerization method is not particularly limited, and a method such as bulk polymerization or solution polymerization may be appropriately employed.
In the case of solution polymerization, aromatic hydrocarbons such as benzene and toluene, lower ketones such as acetone and methyl ethyl ketone, ethyl acetate, chloroform, dimethylformamide and the like can be used alone or in appropriate combination as a solvent. There is no particular restriction on the type of polymerization initiator, and organic peroxides such as benzoyl peroxide, dicumyl peroxide, and lauryl peroxide, azobisisobutyronitrile, azobisdimethylvaleronitrile, and other redox catalyst systems Any of the above can be adopted. In the polymerization, a chain transfer agent such as mercaptans and secondary alcohols can be used. The polymerization temperature is usually about 80 to 140 ° C, and the reaction time is about 2 to 12 hours.

The molecular weight of the obtained water-soluble polymer is usually 1,000 to 1,00
It is about 0,000, preferably 2,000 to 100,000. If the molecular weight is less than 1,000, a sufficient size effect cannot be obtained,
On the other hand, when it exceeds 1,000,000, the viscosity of the aqueous polymer solution tends to increase and the workability tends to be poor.

The surface sizing agent of the present invention contains the above water-soluble polymer as an active ingredient.

The base paper to which the surface sizing agent of the present invention is applied is not particularly limited, and is hardly affected by pulp, filler, internal sizing agent, pH during papermaking, paper strength enhancer, retention end and the like. For example, high-quality paper base paper and coated paper base paper made under acidic conditions, neutral paper-made high-quality paper base paper and coated paper base paper internally sized with alkyl ketene dimer or alkenyl succinic anhydride, etc.
Base paper such as a liner can be used. It can also be suitably used for base paper containing recovered waste paper.

The surface sizing agent of the present invention can be used alone, or can be used in combination with oxidized starch, sodium alginate, carboxymethylcellulose, acrylamide polymers, polyvinyl alcohol, and the like.

The surface sizing agent of the present invention is applied to the above various base papers by a conventionally known coating method, for example, an impregnation method, a size press method, a calender method, or a spray method. The coating amount is usually 0.001 to 5 g / m ² (solid content), preferably 0.1 g / m ² (solid content).
It is a 005~1g / m ^2. Compared with the conventional surface sizing agent, the sizing agent is excellent in dissolving in water, has no drawback of gum up, and has little foaming, so that it can be easily applied to actual machines, and has an excellent sizing effect. Demonstrates the advantage of being able to obtain paper.

〔Example〕

Hereinafter, the present invention will be described specifically with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples. In each example, all parts and percentages are by weight unless otherwise specified.

Example 1 98 parts (50 mol%) of maleic anhydride and 44.6 parts of toluene were charged into a flask equipped with a stirrer, a cooling tube, a dropping funnel, a nitrogen inlet tube, and a thermometer.
The temperature was raised to ° C.

Add diisobutylene (2,4,4-trimethyl-
73.7 parts (25 mol% as 2,4,4-trimethyl-1-pentene) and 1-octene
Charge 56.0 parts (25 mol%) and place in another dropping funnel.
-10.5 parts of butyl peroxybenzoate and toluene
40 parts were charged. These were dropped from the dropping funnel into the flask in about 1.5 hours, and were kept under reflux for about 2 hours.
Thereafter, 4.2 parts of t-butylperoxy-2-ethylhexaate and 20 parts of toluene were added dropwise over about 30 minutes,
Further, the temperature was kept at the same temperature for 1 hour.

The toluene was distilled off under reduced pressure, and the polymer was neutralized with 8 parts of sodium hydroxide, a predetermined amount of water and 109.3 parts of 28% aqueous ammonia to obtain a copolymer aqueous solution. It is a pale yellow suspension with a non-volatile content of 20.5% and a pH of 9.
The viscosity at 0 and 25 ° C was 20 cps.

Examples 2 to 9 Reactions were carried out in the same manner as in Example 1 except that at least one of the kind of the monomer used and the composition thereof was changed to obtain various aqueous copolymer solutions. These constants are shown in Table 1.

Example 10 The whole amount of the copolymer reaction solution obtained in Example 3 before the toluene was distilled off was heated to 70 to 80 ° C, and then ammonium carbonate 1
7.0 parts (NH3 content 30 mol%) were added. The amidation reaction was performed while keeping the temperature at the same temperature for 1 hour.

The toluene was distilled off under reduced pressure, and the polymer was neutralized with 6.8 parts of sodium hydroxide, a predetermined amount of water and 61.2 parts of 28% aqueous ammonia to obtain an aqueous copolymer solution. It is a pale yellow suspension with a non-volatile content of 20.5% and a pH of 9.
The viscosity at 1, 25 ° C was 22 cps.

Examples 11 to 12 The type of copolymer before the amidation reaction and the amidation rate were the first
The reaction was carried out in the same manner except that the composition was changed as shown in the table to obtain various aqueous copolymer solutions. These constants are shown in Table 1.

Comparative Examples 1 to 9 Reactions were carried out in the same manner as in Example 1 except that at least one of the type of the monomer used and the composition thereof was changed to obtain various aqueous copolymer solutions. These constants are shown in Table 1.

The performance evaluation of the surface sizing agent containing various copolymer aqueous solutions obtained above was performed by the following method. The results are shown in Table 2.

(1) Size effect (A) Base paper Acid paper Basic weight 71 g / m ² , Steckhit 0 sec, Internal additive (to pulp addition rate): Talc 20%, Reinforced rosin sizing agent (Arakawa Chemical Industries, Ltd., product) Name “Size Pine E”) 0.05%, Sulfuric acid band 2.5% Neutral paper Basis weight 65g / m ² , Stechigt 0 seconds, Internal additives (to pulp addition ratio): Calcium carbonate 20%, Alkenyl succinic anhydride sizing (Arakawa Chemical Industry Co., Ltd., trade name "Size Pine SA 850") 0.05%, sulfate band 0.5%, cationized starch 0.4%, anionic retention agent (Arakawa Chemical Co., Ltd. trade name "KW- 504 ”) 0.01% (B) Surface sizing equipment: Lab size press Size liquid composition: Oxidized starch (5.0% solids) Aqueous copolymer aqueous solution (0.05% solids) Water (94.95%) Application of size liquid Amount: 2.1 g / m ² of solid content of oxidized starch 0.021 g / m of solid content of the copolymer m ² Drying conditions: by rotary auto drier 130 ° C. × 1 min (C) paper quality evaluation Stockigt sizing degree JIS P-8122.

 Cobb size Degree according to JIS P-8140.

(2) Solubility in water 140 parts of water was added to 40 parts of the polymer powder obtained by sampling immediately after the toluene distillation step in each of the above examples,
Further, a 48% aqueous sodium hydroxide solution and 28% aqueous ammonia were added and stirred so that the neutralization ratio with respect to the carboxyl group became 100%, and the solubility of the polymer powder in water was visually evaluated.

場合 indicates easy dissolution, △ indicates partial dissolution, and × indicates little dissolution. Neutralization rate: sodium hydroxide / ammonia = 10/90 (mol%) (3) Acid stability The transmittance A of the aqueous solution of the surface sizing agent (solid content 0.2%),
The transmittance B when adjusting the pH to 3.5 by adding 1 / 2N sulfuric acid to the aqueous solution was measured using 420 nm light, and B / A
Was evaluated as ○ when the value was 0.8 or more, and × when the value was 0.7 or less.

(4) Foamability 1000 parts of a size liquid to which 5% of oxidized starch and 0.05% of a surface sizing agent were added were put into a cylindrical flask of 2, and kept at 45 ° C. The mixture was stirred at 4000 rpm for 10 minutes with a 3-blade propeller stirrer, and the foaming amount was measured.

[Effect of the Invention] The surface sizing agent of the present invention is superior to conventional surface sizing agents in dissolving in water, has no gum-up disadvantages, and is easy to apply to a real machine because of less foaming. In addition, there is an effect that a paper having an excellent size effect can be obtained.

Continuation of front page (56) References JP-A-60-146098 (JP, A) JP-A-55-67094 (JP, A) JP-A-59-78207 (JP, A) JP-B-46-2124 (JP) , B2) (58) Field surveyed (Int. Cl. ⁶ , DB name) D21H 1/34, 3/38

Claims (4)

(57) [Claims] (A) α, β-unsaturated polycarboxylic acid or its salt unit (component (a)) 30 to 70 mol% (b) 2,4,4-trimethyl-1-pentene ((b) (C) a linear α-olefin having 8 to 20 carbon atoms (component (c)) 60 to 5 mol%, and (b) / (c) is 8/2. A surface sizing agent comprising, as an active ingredient, a water-soluble polymer having a composition ratio of about 2/8. 2. (a) α, β-unsaturated polycarboxylic acid or its salt unit (component (a)) 30 to 70 mol% (b) 2,4,4-trimethyl-1-pentene ((b) (Component) 5 to 60 mol% (c) linear α-olefin having 8 to 20 carbon atoms (component (c)) 60 to 5 mol% and (d) other monomer unit (component (d)) 0 A surface sizing agent comprising, as an active ingredient, a water-soluble polymer having a composition ratio of (b) / (c) of from 8/2 to 2/8. 3. The surface sizing agent according to claim 1, wherein 10 to 90 mol% of the component (a) is a half amide. 4. The surface sizing agent according to claim 1, wherein the component (c) is a linear α-olefin having 9 to 14 carbon atoms.