JPS61261302A - Production of cationic polymer latex - Google Patents

Abstract

PURPOSE:To produce the titled latex high in the density of surface charges on the cationic particles, by polymerizing a specified ethylenically unsaturated monomer mixture in the presence of a chain transfer agent, adding the remaining portion of the monomer mixture to the obtained seed latex and polymerizing the resulting mixture. CONSTITUTION:A seed latex is obtained by polymerizing at most 50wt% portion of a monomer mixture comprising 1-70wt% ethylenically unsaturated monomer containing a sec. or tert. amine or quat. ammonium salt of formula I (wherein R1 is H or methyl, R2 is a 2-10C alkylene, R3-4 are each H or a 1-12C alkyl and A is -O- or a group of formula II or III) and 99-30wt% ethylenically unsaturated monomer (e.g., isoprene) copolymerizable therewith at 5-80 deg.C in an aqueous medium of a pH 2-7 in the presence of 0.05-30pts.wt., per 100pts.wt. this monomer mixture, chain transfer agent with the aid of a radical polymerization initiator. The remaining portion of this monomer mixture is added to the seed latex and the polymerization is continued.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a method for producing a cationic polymer latex suitable for internal addition to various fibers.

(Prior Art) Papermaking has conventionally been carried out using fibers such as cellulose and ordinary anionic polymer latex as a binder. Since cellulose fibers and polymer latex have the same charge, it is necessary to use a fixing agent such as sulfuric acid/gundo to fix the gundo latex onto the fibers.

By adding a fixing agent, the latex rapidly envelops the fibers and coagulates, resulting in large fiber flocs and the strength of the resulting paper being reduced due to insufficient intertwining of the fibers. '1, fiber 70. It is not enough because the shape of the hole is still retained. Furthermore, since the commonly used anionic surfactant remains in the papermaking process, sufficient water resistance cannot be obtained.

It is also known to use cationic polymer latex for internal addition to cellulose fibers, pulp, etc., but if latex polymerized using a normal cationic surfactant is used for internal addition, cationic surfactant Although the agent has bactericidal properties, in practical use, a problem arises in that the activated sludge for biodegradation is deactivated by the cationic surfactant in the wastewater, causing environmental pollution. In addition, simply carrying out emulsifier-free polymerization in an aqueous medium can only be carried out at a polymer concentration of about 20% by weight or less, which is expensive in terms of cost if carried out industrially.

A method for producing a cationic polymer latex in which a cationic monomer is copolymerized with other monomers by seed polymerization without using an emulsifier or using a cationic emulsifier is disclosed in JP-A-57-121048. Publication and JP-A-59-142
It is known from the publication No. 217. In these methods, a seed latex is made using the entire amount of the cationic monomer and a portion of other monomers, and the remaining monomers are added to this to obtain the desired polymer latex. . Compared to the method in which all the monomers used are charged into a reaction vessel at once and polymerized, this method allows multistable polymerization because the number of particles is determined by the seed latex and no new particles are generated. However, in these methods, the remaining monomers are polymerized on the surface layer of the seed latex, so-called Core-5hell.
Because a structured latex is formed, many cationic groups, which greatly contribute to the stability of latex particles, are present inside the particles, and many cationic groups cannot be present on the particle surface, resulting in a stable latex particle. Cannot polymerize. Therefore,
Because the surface charge density of cationic particles in the latex obtained was insufficient compared to the amount of cationic groups used, papermaking using the cationic polymer latex obtained by this method as a binder for internal addition to fibers Because it does not have enough charge as a binder, the fibers are weakly entangled and have poor toughness, which requires improvement.

(Problems to be Solved by the Invention) The present inventors have conducted intensive studies to develop a method for producing a cationic polymer latex in which cationic groups are densely distributed on the surface of latex particles, and have found that in the seed polymerization described above, discovered that when forming seed latex, polymerization could be carried out in the presence of a chain transfer agent, and based on this knowledge, completed the present invention.

(Means for Solving the Problems) Thus, according to the present invention, at least one ethylenically unsaturated monomer (a) having a secondary or tertiary amine or a quaternary ammonium salt (1-70 Weight% and monomer (
(1) When producing a cationic polymer latex by radical polymerizing 99 to 30% by weight of at least one type of ethylenically unsaturated monomer (b) copolymerizable with polymers in an aqueous medium, (1) the above monomers; A seed latex is obtained by polymerizing a part of compounds (a) and ←) using a radical polymerization initiator in the presence of at least 0.05 parts by weight of a chain transfer agent per 100 parts by weight of the monomer mixture. (2) Then, the remaining monomers are added to continue the polymerization.

The tertiary amine or quaternary ammonium salt-containing ethylenically unsaturated monomer (a) used in the present invention imparts cationic properties to the polymer latex (hereinafter referred to as cationic properties imparting monomer). Sometimes). The secondary or tertiary amine-containing ethylenically unsaturated monomer has the general formula (in the formula, R1 is hydrogen or a methyl group, R2 is an alkylene group of 02-1o, R3 and R4 are hydrogen or C1-,2 The alkyl group is -C-O-, -C-S, or -
Examples include monomers represented by 〇-group), heterocyclic nitrogen-containing ethylenically unsaturated monomers, and the like.

Examples of the monomers represented by the above general formula include methylaminoethyl (meth)acrylate, t-butylaminoethyl (meth)acrylate, dimethyl-aminoethyl (meth)acrylate, diethylaminoethyl (meth)acrylate, and diethylaminoethyl (meth)acrylate. meta) acrylate,
Ethylenically unsaturated calcium such as diptylaminoethyl (meth)acrylate? Aminoalkylamides of ethylenically unsaturated cargenic acids such as methylaminoethyl (meth)acrylamide, dimethylaminoethyl (meth)acrylamide, dimethylaminopropyl (meth)acrylamide; aminoethyl vinyl ether, methylaminoethyl Heterocyclic nitrogen-containing ethylenic saturated monomers such as aminoalkyl vinyl ethers such as vinyl ether and dimethylaminoethyl vinyl ether include 2-vinylpyridine, 4-vinylpyridine, 2-methyl-5-vinylpyridine 12.4-dimethyl -vinylbilicin, 1-methyl-2-vinylquinoline, N-vinyl-methylimidazole, and the like.

Examples of the quaternary ammonium salt-containing ethylenically unsaturated monomer include 2-hydroxy-3-methacryloxypropyltrimethylammonium chloride, 2-hydroxy-3-methacryloxypropyltrimethylammonium chloride, and 2-hydroxy-3-methacryloxypropyltrimethylammonium chloride. Acryloxypropyltrimethylammonium chloride, 2-hydroxy-3-methacryloxypropyltrimethylammonium chloride, 2-hydroxy-3-methacryloxypropylmethylethylbutylammonium chloride, 2-hydrocycetate 3-methacryloxypropyl dimethyl Phenylammonicum chloride, 2-
Examples include hydroxy-3-methacryloxypropyldimethylcyclohexylammonium chloride. One or more of the above cationic property-imparting monomers are used.

The amount of one or more of these monomers used is 1 to 7 of the total monomers.
If the amount is less than 1% by weight, the copolymerization rate of the cationic monomer is low and stable particles cannot be obtained,
If it exceeds 70% by weight, stable polymerization without coagulum cannot be carried out in aqueous medium polymerization. Preferably 1
~40% by weight.

Ethylenically unsaturated monomers copolymerizable with the above-mentioned cationic property-imparting monomers used in the present invention include, for example, isoprene, 1,3-butadiene, 2-methyl-1,3-
Butadiene, 2-chloro-1,3-butadiene, 1,3
- Conjugated diene monomers such as pentadiene; styrene, α
- Aromatic vinyl compounds such as methylstyrene, sonochlorostyrene, and vinyltoluene; Unsaturated nitrile compounds such as acrylonitrile, methacrylonitrile, and α-chloro-acrylonitrile; Methyl (meth)acrylate, ethyl (meth)acrylate, butyl ( meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, hydrocow diethyl (meth)acrylate, hydroxypropyl (meth)acrylate,
Esters of unsaturated monocarboxylic acids such as glycidyl (meth)acrylate; unsaturated dicarboxylic acid diesters such as dimethyl fumarate, dimethyl maleate, diethyl itaconate; (meth)acrylamide, N-methylol (
Examples include unsaturated amides such as meth)acrylamide and N-methoxymethyl(meth)acrylamide, and their N-substituted derivatives, and one or more of these may be used.

The amount of the monomer copolymerizable with these cationic property-imparting monomers is 30 to 99% by weight based on the total monomers. If the amount used is less than 30% by weight, a coagulated product will be generated that makes it difficult to proceed with stable polymerization, and if it exceeds 99% by weight, the copolymerization rate of the cationic monomer will be low and stable polymerization will occur. Coalesced latex cannot be obtained. Preferably it is 60 to 99% by weight.

The method for producing a cationic polymer latex of the present invention includes a step of producing a seed latex by radical polymerization in an aqueous medium using a part of the above monomers, and adding the remaining monomers to this seed latex. The method of the present invention is characterized by carrying out polymerization in the presence of a chain transfer agent in the step of producing a seed latex.

For the production of seed latex, 50% of the total amount of all the monomers mentioned above is used.
It is desirable to use monomers by weight below. If it exceeds 50% by weight, the particle size of the seed latex becomes too large and the stability of the latex decreases. More preferably it is 30 weight or less, and even more preferably 200 weight or less. The lower limit of the amount used depends on the particle size of the desired final polymer latex, and is not particularly limited in the present invention. Among the monomers used for producing the seed latex, the amount of the cationic monomer used is preferably 20% by weight or more of the total amount used. If less than 20% by weight is used, the presence of cationic groups on the surface of the final polymer latex particles will be insufficient and a large amount of coagulum will be generated during the production of the final latex. It is preferably at least 30% by weight, more preferably at least 40% by weight.

These monomers are polymerized in an aqueous medium using a radical initiator to produce a seed latex. At this time, the presence of a chain transfer agent is essential to increase the surface charge density of cationic particles in the final latex. be.

Chain transfer agents used in the present invention include mercagutans such as n-ttermerkabutane, n-octylmercaptan, n-lacrylmercaptan, n-dodecylmercaptan, and t-dodecylmercaptan; carbon tetrabromide, carbon tetrachloride; Heronated derivatives such as
More than one species is used. The amount of chain transfer agent used is 10 monomers.
0 parts by weight, i = 0.05 parts by weight or more. 0.0
If it is less than 5 parts by weight, the effect of increasing the cationic charge density on the surface of the final latex particles will not be obtained, and a large amount of coagulated matter will be generated during the polymerization process of the final latex.

Preferably it is 0.1 part by weight or more. When the amount used is 30 parts by weight or more, the molecular weight of the latex polymer decreases,
In the process of polymerizing the final latex, agglomeration of particles occurs and a large amount of coagulation is generated, which is not preferable. Preferably it is 20 parts by weight or less. Polymerization is nonionic and/or
Alternatively, it may be in the presence or absence of a cationic emulsifier, but in consideration of waste water treatment after using the cationic polymer latex, it is preferable not to use an emulsifier.

As the emulsifier, a nonionic emulsifier used in normal emulsion polymerization or N-ethyldodecyl ammonium bromide,
Cationic emulsifiers such as cetyl ammonium chloride, N,N-dimethyldodecyl ammonium chloride, and mixtures of both emulsifiers can be used.

The radical polymerization initiator used in the present invention may be a nonionic polymerization initiator or a cationic polymerization initiator used in ordinary emulsion polymerization, and is not particularly limited.

Examples of nonionic polymerization initiators include hydrogen peroxide, pensoyl peroxide, t-butyl-hydronog-oxide, diisoglobylbenzene hydroperoxide,
Hydronos such as cumenehypyrono9-ogisite, azobisisobutyronitrile, 2.2'-
Redox systems that combine aliphatic azo compounds such as azobis(2,4-dimethylvaleronitrile), the above-mentioned hydroperoxides, and reducing agents such as ascorbic acid, polyvalent metal salts, and sodium formaldehyde sulfoxylate, etc. can be mentioned. 2.2 as a cationic polymerization initiator
Examples thereof include 7-azobis(2-amidinopronoyan) hydrochloride, azobis(N,N'-dimetheleneisotylamidine) hydrochloride, and the like. The amount of these polymerization initiators to be used may be according to a conventional method and is not particularly limited in the present invention. The mode of polymerization is also not particularly limited in the present invention, and may be batchwise,
It may be of any type, such as a continuous type. Furthermore, the polymerization temperature may range from a low temperature (usually 5°C) to a high temperature (usually 50°C to 80°C).

The voice of the polymerization system may be any voice, but it is preferably in the range of 2 to 7 in order to increase the surface density of the latex particles of cationic groups.

The remaining monomers are added to the seed latex thus obtained to continue the polymerization. At this time, a radical polymerization initiator and/or a chain transfer agent can be added if necessary.

The mode of polymerization is the same as in the production of seed latex.

According to the method of the present invention, the polymerization reaction can proceed stably, and a cationic polymer latex having a high concentration and a high cationic charge density on the particle surface can be produced without the generation of coagulated substances.

The latex produced by the method of the present invention is particularly suitable for internal addition to various fibers. The ratio of the conjugated diene monomer and the monoethylenically unsaturated monomer other than the cationic monomer is suitable as an ingu, and the glass transition temperature of the cationic polymer is 180°C to 20°C. It can be determined according to the required characteristics.

The present invention will be explained in more detail with reference to Examples below. Note that parts and parts in the examples are based on weight unless otherwise specified.

Example 1 In an autoclave equipped with a stirrer, according to the polymerization recipe in Table 1,
After adding water and dimethylamine ethyl methacrylate, adjust the volume in the system to 3 with hydrochloric acid, then add styrene, t-
2. Prepare dodecyl mercaptan and heat to 60°C.
2'-Azobis(2-amidinopropane) hydrochloride was added to initiate the reaction.

Polymerization was carried out to a polymerization addition rate of 98 or more (measured by gravimetric method) to complete the reaction of the seed latex.

Table 1 (Seed latex polymerization recipe) Immediately after this reaction, 260 parts of styrene and 3 parts of butadiene were added to the seed latex.
06 parts were added continuously over 4 hours. At the same time as the addition of the monomer dispersion, the redox polymerization initiator shown in Table 2 was also added. During this time, the temperature of the autoclave was 60℃.
I kept it. The reaction was continued until the reaction conversion rate reached 98 degrees or more.At the reaction conversion rate of 498 degrees or more, the autoclave was cooled to room temperature to stop the reaction.The obtained cationic copolymer latex had a solid content of Concentration 39.6chi, pH 4
, 3, and the isoelectric point was 9.1.

Table 2 (Redox polymerization initiator composition) A cationic copolymer latex of a comparative example was obtained in exactly the same manner as the polymerization recipe shown in Table 1 except that t-dodecyl mercaptan was omitted. The obtained latex was filtered through a 150-mesh wire mesh,
When the coagulum remaining on the wire mesh was measured, it was found to be about 0.02% in the latex of the present invention and about 5% in the latex of the comparative example.

The amount of amine on the particle surface of the obtained latex was determined by the conductivity titration method of Kawaguchi et al.
l, sJ, Appl, Polym@r Sci,
, vol 26, 2015 (1981)). Latex is made from cellulose chip (UCC).
Company# Seamless Ce1lulose Tub
Dialyzed in running water for 10 days using a latte (size 36/32) to obtain a solid content of 4%. 1
After adding 15 m of 20% aqueous solution of Toshie Margun 147 (manufactured by Kao Soap Co., Ltd.) to a 00crILs beaker, add N15
Adjust the - to 12 with NaOH and titrate the conductivity with N/10 HCA. (For conductivity, use CM-117 manufactured by Kyoto Electronics Industry Co., Ltd.) For titration from the second bending point to the third bending point. The required amount was taken as the amine amount (the same applies to the following examples)
. The results are shown in Table 3.

Table 3 (Amount of amines on the surface of latex particles) It can be seen from Table 3 that in the examples of the present invention, more cationicity-imparting groups are present on the particle surfaces than in the comparative examples.

Example 2 A seed latex was produced in the same manner as in Example 1 according to the seed latex polymerization recipe shown in Table 4.

Table 4: WIi2 Te, Cu polymerization recipe 220 parts of acrylonitrile added to the seed latex immediately after production.
346 parts of butadiene were added. At the same time, a redox polymerization initiator shown in Table 5 was also added.

Table 5 (Redox polymerization initiator composition) A cationic copolymer latex of a comparative example was obtained in exactly the same manner as shown in Table 4 except that t-dodecyl mercaptan was omitted. The coagulated product after polymerization was about 0.13% in the present invention example and about 1 ots in the comparative example.The amount of amine on the surface of the obtained latex was measured in the same manner as in Example 1. The results are shown in Table 6.

Table 6 (Amount of amine on the surface of latex particles) Next /f Merck NBKP) 10? was added to a disintegrator (manufactured by Tester Sangyo Co., Ltd.) together with 1.5 dm' of water and stirred for 5 minutes. After that, talc (5S manufactured by Nippon Talc Co., Ltd.) 40? After adding and stirring for 1 minute, latex 60? (Solid content concentration 1
2.5'16) was added. After the addition, the mixture was stirred for 19 minutes, 10 cm'' (concentration 5%) of Aron T-40 (manufactured by Toagosei Co., Ltd.) was added, the latex was completely fixed on the nokrug, and the mixture was further stirred for 5 minutes.

The entire amount of the obtained Noel Gutarx slurry was passed through a hand paper tester (
Tester Sangyo Co., Ltd.) to make paper, remove water, and then heat to 90°C.
After drying by placing it on a hot plate for 10 minutes, it was placed on a hot roll at 130° C. and a roll pressure of 301#/α2 to increase the density. The obtained paper was placed on a test piece of 1×15cIL and chucked with a tensioner (manufactured by Toyo?-Rudtsin Co., Ltd.) with a chuck distance of 10c*.
A tensile test was conducted at a tensile speed of 300WIIy'min to determine the fracture length. In addition, a 5×2 cIL test piece was prepared and its weight was measured.

To evaluate water resistance, test pieces were fixed to wires and immersed in a large test tube with a reflux condenser containing distilled water so that they did not touch each other, and heated in an oil path at 100°C for 5 hours. After taking out the test piece and lightly absorbing water with a towel pen (manufactured by Jujo Kimbari), measure the weight of the test piece, divide the weight increase due to immersion by the weight before immersion, and calculate the weight change rate. And so.

Pulp Merck paper was made using the present latex and comparative latex, and for comparison, paper was made using N1pol 1571 (acrylonitrile-butadiene copolymer latex manufactured by Nippon Zeon Co., Ltd.) as an anionic latex in the same manner. Table 7 shows the tear length and weight change rate due to distilled water immersion with papermaking paper (Aron T-40 glue DK pan sulfate ± 10 cm" (concentration 5 cm) is used) and weight change rate due to distilled water immersion. Values in Table 7 is the average value of four test pieces.

Table 7 (Tear length and weight change rate for papermaking) This table shows that the papermaking using the cationic latex of the present invention is different from the papermaking using the latex of the comparative example and the conventional anionic latex. It can be seen that the toughness and water resistance are significantly improved.

Example 3 A seed latex was produced in the same manner as in Example 1 according to the seed latex polymerization recipe shown in Table 8.

Table 8 (Seed latex polymerization recipe) This seed latex contains 90 parts of ethyl acrylate and 10 parts of water.
A polymerization initiator in which 0.8 part of 2,2'-azobis(2-amidinopro/4-one) hydrochloride was dissolved was added to the mixture, and the polymerization was continued to obtain a cationic copolymer cake. Also, as shown in Table 5, cationic copolymer esters and esters were also obtained in the same manner as above except that 9t-dodecyl mercaptan was omitted. The amount of coagulated material after polymerization was approximately 0.01'16% in the present invention example, and approximately 30% in the comparative example. The amount of amine on the particle surface of the obtained LX was examined in the same manner as in Example 4, and the results were reported in Example 9.
Shown in the table.

Claims (1)

[Scope of Claims] 1 to 70% by weight of at least one ethylenically unsaturated monomer (a) having a secondary or tertiary amine or a quaternary ammonium salt; At least one copolymerizable ethylenically unsaturated monomer (b) 99-30
When producing a cationic polymer latex by radical polymerizing % by weight in an aqueous medium, (1) A part of the above monomers (a) and (b) is added per 100 parts by weight of the monomer mixture. (2) producing a seed latex by polymerizing with a radical polymerization initiator in the presence of at least 0.05 parts by weight of a chain transfer agent; (2) then continuing the polymerization by adding the remaining monomers; A method for producing a characteristic cationic polymer latex.