JPS5821656B2 - Latex materials that can be used for various purposes - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a block copolymer latex composition with improved film-forming properties.

Synthetic rubber latex is generally produced by emulsion polymerization and is widely used.

However, in recent years, with the rapid progress of polymerization technology, unique solution polymerization type synthetic rubbers have been produced for many years, and attempts have been made to use these as latexes.

The general method for obtaining latex from this type of solution-polymerized synthetic rubber is to add an emulsifier and water to a rubber polymerization solution or solid rubber dissolved in a suitable solvent to make a solution, and then emulsify the resulting solution. This is done by removing the solvent from the emulsion by stripping, flushing, distillation, or the like.

Furthermore, if the latex thus obtained is dilute, it is also known to concentrate it by operations such as creaming, centrifugation, evaporation, etc., if necessary.

One of the characteristic synthetic rubber latexes obtained by this method is a block copolymer latex in which inelastic blocks A made of an aromatic vinyl compound and elastomer blocks B made of a conjugated diene compound are alternately present.

This block copolymer has the general formula %) (A-B+nA or A-B(B-A)n (where A is an inelastic block made of an aromatic vinyl compound, and B is an elastic block made of a conjugated diene compound). body block,
n represents an integer of 2 or more.

).

Generally, the A block has a second order transition temperature of 25°C or more, and the B block has a second order transition temperature of 10°C or less, and is called a thermoplastic elastomer, and is usually crosslinked with a sulfur compound etc. Even without vulcanization, it exhibits high strength, elongation, and low residual strain comparable to ordinary vulcanized rubber.

Latex made from such block copolymers has the above-mentioned unique properties and features that are in a latex state compared to conventional solvent-dissolved types, such as high solid content, relatively low viscosity, and quick drying. , water is a solvent, so it is not flammable or toxic, and it does not contain photochemically reactive substances and does not pollute the air. It has a wide range of applications, including rubber thread, carpet back sizing agents, paper processing agents, fiber processing agents, surface coating agents, adhesives, paint binders, latex-added asphalt, and cement compounding agents.

However, when block copolymer latex is used for the above-mentioned purposes, it may have major drawbacks depending on the processing conditions.

That is, if water does not evaporate at a temperature higher than a certain humidity during the process of forming a film from the block copolymer, a continuous and uniform film will not be formed.

Generally, the lowest temperature at which a continuous and uniform film is formed is the minimum film forming temperature (hereinafter abbreviated as MFT).

).

It is said that the MFT of normal latex shows a strong correlation with the second-order transition temperature of the polymer that is the main component, and even in the case of block copolymers, it is usually difficult to form a film at around room temperature. Unless it is heat-treated at a temperature below the next transition temperature, it will not exhibit its unique properties.

As methods for lowering MFT, methods such as internal plasticization, external plasticization, and temporary plasticization are known.

Among these methods, the internal plasticization method is based on changing the copolymerization ratio in the copolymer latex, but although it is effective for random copolymers, it is not effective for block copolymers. This is not necessarily a preferable method because it cannot be expected to be effective and the unique properties of the block copolymer itself change.

Next, as for the external plasticization method, a method in which a plasticizer such as dibutyl phthalate is added to the latex is known, but it has the drawback that although the MFT is lowered, the strength of the film formed from the latex is significantly lowered.

Furthermore, the temporary plasticization method involves adding a solvent such as benzene or toluene, which may reduce the MFT, and although the film formed from the latex has sufficient physical properties, it requires the use of a relatively large amount. , and has the major disadvantage of significantly lowering the mechanical stability of latex when added, and generating a large amount of precipitation and agglomerates.

The present inventors have conducted extensive research in order to solve the drawbacks of conventional methods regarding lowering the MFT of block copolymer latex, and have found that block copolymer latex and certain specific solvents and certain A composition was obtained in which the aldehyde condensate of a specific phenol was combined with a compound to which ethylene oxide was added.

This composition had improved film formability and high mechanical stability.

That is, the present invention provides a) a block copolymer latex consisting of an aromatic vinyl compound and a conjugated diene compound; 4 to 40 parts by weight per 100 parts by weight of the copolymer, and c) aldehyde condensation of phenols represented by the following general formula (I); a compound obtained by adding ethylene oxide to 100 parts by weight of the block copolymer. The object of the present invention is to provide a block copolymer latex composition with improved film-forming properties, which contains 0.2 to 8 parts by weight based on the composition of the present invention.

General formula (where R1 is an aryl group, an aralkyl group, or an alkyl group having 8 to 18 carbon atoms, R2 is hydrogen or an alkyl group having 8 or less carbon atoms, n and m are integers of 1 to 3, and n+m is 5 or less, and when n or m is 2 or more, R1 or R2 may be different from each other.

) The block copolymer used in the present invention has the general formula %) ) ) (where A is an inelastic block made of an aromatic vinyl compound, B is an elastic block made of a conjugated diene compound,
n represents an integer of 2 or more.

) with a molecular weight of 10,000 to 500,00
0, and the content of component A is 10 to 7 based on the total polymer.
0 weight percent block copolymer.

These can be polymerized by a living anionic polymerization method using an alkali metal-based initiator.

Preferred aromatic vinyl compounds forming the inelastic block include styrene, α-methylstyrene vinyltoluene, etc., and may be a homopolymer or a copolymer of two or more types.

Preferred conjugated diene compounds forming the elastic block include 1,3-butadiene and isoprene, which may be homopolymers or copolymers of two or more; A random copolymer of a compound and an aromatic vinyl compound may also be used.

Such block copolymers can be produced by sequentially polymerizing monomers block by block in the presence of the initiator, or by simultaneously charging and polymerizing two or more monomers having different copolymerization reactivity ratios. It can be obtained by a method of obtaining a living block copolymer or a method of coupling with a living block copolymer using the above-mentioned initiator.

The block copolymer represented by the general formula AB(E-B-A)n can be obtained by coupling a living block copolymer of A-BO with a polyfunctional coupling agent, for example, When a tetrafunctional coupling agent such as tin tetrachloride is used, a block copolymer having the structure is obtained.

The molecular weight of the block copolymer is i o, o o o or 500,000. If the molecular weight is less than 10,000, the mechanical strength of the film obtained from the latex will be poor, and if the molecular weight exceeds 500,000, it will be difficult to solve the problem during emulsification. The viscosity becomes too high, resulting in incomplete or difficult emulsification.
adversely affects the properties of the latex obtained.

Inelastic block portion in the block copolymer, that is, A
The content of the components can be selected within the range of 10 to 70% by weight based on the total polymer; anything outside this range is not preferred because the properties of the thermoplastic elastomer will be poor.

The block copolymer latex, which is the first component of the composition of the present invention, can be produced using the above-mentioned block copolymer by the general method of obtaining latex from the solution-polymerized synthetic rubber described above. When removing the solvent from the emulsion after emulsification and concentrating the resulting dilute latex, a large amount of precipitated coagulum occurs, resulting in extremely poor growth and poor mechanical stability of the final product. Problems tend to arise and it is never easy.

As a method for producing a block copolymer latex which solves the above problems, there is Japanese Patent Application No. 49-92148 or No. 50-4264 which precedes the present application.

Japanese Patent Application No. 49-92148 discloses that (a) a rosinate salt or a disproportionated rosinate salt and (b) an HLB value of 12 are used as emulsifiers when producing a latex of a glue copolymer.
to 17 nonionic surfactants, a colloid mill type emulsifier is used as the emulsifier], and the emulsification is carried out at a linear velocity of 2000 m/min or more at the tip of the emulsifier.

Furthermore, Japanese Patent Application No. 1983-4264 discloses that (1) a compound selected from higher fatty acids, rhodinates, dialkyl sulfosuccinates, alkylbenzenesulfonates, and mono- or dialkylnaphthalenesulfonates is used as an emulsifier when producing a polymer latex. 0.5 to 15 parts by weight of one or more anionic surfactants per 100 parts by weight of the polymer; (2) phenols having two or more aromatic nuclei at least in part; The method is characterized in that 0.5 to 15 parts by weight of a nonionic surfactant consisting of an ethylene oxide adduct of 1 is used per 100 parts by weight of the polymer.

The block copolymer latex, which is the first component of the composition of the present invention, may be produced by the IgaNaru method, but it may be a latex with excellent mechanical stability obtained by the above-mentioned method or the like. It is preferable that there be.

Hydrocarbons with a boiling point of 150 to 250°C used in the present invention,
Examples of the halogenated hydrocarbon or ester compound include the following.

Hydrocarbon solvents such as n-decane, diethylbenzene, impropinebenzene, amylbenzene, amyltoluene, P-cymene, naphthalene, tetralin, decalin, dipentene, mesitylene, α or β pinene, P-menthane, and mixtures thereof, kerosene, Spreading vegetable oils such as turpentine oil, pain oil and camphor oil.

Pentachloroethane, hexachloroethane, 1゜2,
Halogenated hydrocarbons such as 3-trichloropropane, tetrabromoethane, O-dichlorobenzene, 1,2.4-)dichlorobenzene, bromobenzene, 0-dibromobenzene, 0-chlorotoluene, P-chlorotoluene, etc. and mixtures thereof.

Esters such as ethylene acetate, 2-ethylbutyl acetate, 2-ethylhexyne acetate, isoamine butyrate, butyl butyrate, ethyl acetoacetate, ethyl lactate, butyl lactate, methyl benzoate, methoxybutyl acetate, 2-ethylbutyl acetate, cyclohexyl acetate, benzyl acetate, etc. and mixtures thereof.

The solvent, which is the second component of the present invention, is mainly composed of the above-mentioned hydrocarbons, halogenated hydrocarbons, or ester compounds with a boiling point of 150 to 250°C, and other solvents (for example, carbonized It is also possible to use a mixture of hydrogen solvents (hydrogen solvents), but it is necessary that at least 25% by weight thereof consists of the above-mentioned compounds.

The amount of solvent is 4 to 4 per 100 parts by weight of the copolymer.
0 parts by weight, preferably 10 to 30 parts by weight.

If it is less than 4 parts by weight, the effect of MFT improvement will not be sufficient, and 40 parts by weight or less will be insufficient.
Although the MFT improvement effect is sufficient beyond the weight part,
This is undesirable because it takes time for the solvent to evaporate after film formation, and the features of the latex emulsion form, such as non-toxic, non-polluting or non-hazardous properties, are lost.

The third component of the present invention, a compound obtained by adding ethylene oxide to the aldehyde condensate of phenols represented by the general formula (1), is generally commercially available as various grades of Pionin D (trade name) of Monomoto Yushi ■. and can be created as follows.

That is, phenols represented by the general formula (1) and aldehydes such as formaldehyde are reacted by heating in an ethanol solution in the presence of hydrochloric acid, the resulting product is dissolved in toluene, and ethylene oxide is reacted in the presence of sodium hydroxide. It is obtained by injecting.

Examples of the phenols represented by the general formula (I) include octylphenol, nonylphenol, phenylphenol, benzylphenol, tolylphenol, α
- or β-phenylethylphenol, phenylpropylphenol, biphenylylphenol, benzyloxyphenol, benzylthiophenol, phenylacetylphenol, phenacylphenol, benzoylphenol, naphthylphenol, phenylcresol, benzylcresol, α- or β-phenyl Examples include ethyl cresol and polyphenylalkylphenol.

The degree of polymerization of these aldehyde condensates of phenols is preferably from 2 to 9; increasing the degree of polymerization more than that is meaningless in terms of effectiveness, and results in poor solubility, making handling difficult.

The amount of ethylene oxide added is shown by formula (1) so that the HLB value (HLB = E15, E is the ethylene oxide content (weight percent) relative to the whole), which indicates surface activity, is 6.7 to 16.7. The amount is preferably 50 to 500 parts by weight per 100 parts by weight of the aldehyde condensate of phenols.

This ethylene oxide addition portion may partially contain propylene oxide as a random or block copolymer.

The composition of the present invention contains 0.2 to 8 parts by weight, preferably 0.2 to 8 parts by weight, per 100 parts by weight of the copolymer, of a compound obtained by adding ethylene oxide to an aldehyde condensate of phenols represented by the above general formula (1). It contains 0.5 to 5 parts by weight.

If it is less than 0.2 parts by weight, the effect will not be sufficiently exhibited,
Moreover, if the amount exceeds 8 parts by weight, the viscosity of the composition increases more than necessary, making handling difficult, and the physical properties in the final use, such as the tensile properties and adhesive properties of the film, are deteriorated, which is undesirable.

The book copolymer latex composition of the present invention comprises the above-mentioned 3
It can be easily obtained by mixing the components simultaneously, but other methods such as changing the mixing order may also be used.

It is also possible to use the final product immediately after mixing, but if you want to use it particularly effectively, it is preferable to let it ripen for at least 1 hour.

One way to shorten this aging time is to make an aqueous emulsion using a compound in which ethylene oxide is added to an aldehyde condensate of a solvent as a second component and an aldehyde condensate of phenols as a third component, and water. There is a method of mixing it with the component block copolymer latex.

The block copolymer latex composition of the present invention can be applied to the wide range of uses mentioned above, but it can also be used in combination with natural rubber latex or other synthetic rubber latex.

It can also be used in combination with emulsions or aqueous solutions of plastics such as urethane resins, acrylic resins, epoxy resins, vinyl acetate resins, and ethylene-vinyl acetate copolymer resins.

A thickener can also be added to the block copolymer latex composition of the present invention to increase the viscosity.

As the thickener, methylcellulose, carboxymethylcellulose, hydroxymethylcellulose, casein, polyvinyl alcohol, polyacrylic acid or its derivatives, sodium salt or ammonium salt of polyacrylic acid, etc. can be used.

A filler in the block copolymer latex composition of the present invention,
Anti-aging agents, colorants, dispersion stabilizers, etc. may be added as necessary.

Examples of fillers include inorganic fillers such as aluminum carbonate, clay, talc, hydrated silicic acid, anhydrous silicic acid, magnesia, zinc white, carbon black, and barium sulfate.

As the anti-aging agent, those generally used in the rubber industry are suitable, and anti-aging agents may also be included.

Furthermore, as for the coloring agent, inorganic and organic coloring agents may be used as necessary.

Examples of dispersion stabilizers include the following, which are commonly known as dispersion stabilizers for latex compounding.

Naphthalene sulfonate, condensed alkylnaphthalene sulfonate, condensed naphthalene sulfonic acid, potassium oleate, oleyl sulfate, polyoxyethylene alkyl allyl ether, polyacrylic acid polymer surfactant,
Alkyl ether type nonionic surfactant, polyoxyethylene, polyoxypropylene type surfactant.

The present invention will be explained in more detail with reference to the following Reference Examples, Examples, and Comparative Examples, but the contents of the present invention are not limited thereto.

The mechanical stability, MFT1 maximum tensile strength and elongation of the composition were measured as follows.

That is, mechanical stability was determined by the method of JISK-6381.

MFT was measured using a thermal gradient tester.

The maximum tensile strength and elongation were determined according to the method of JISK-6310 after one day of film formation on a film having a thickness of about 0.1 ml and formed by casting on a glass plate.

Reference example 1 Thermoplastic elastic body made of styrene and butadiene block copolymer obtained by solution polymerization (Tsurprene T414) 1
Dissolve 2 parts by weight of disproportionated rosin acid and 4 parts by weight of polyoxyethylene nonylphenyl ether with an HLB value of 15.0 in a 33% by weight toluene solution containing 00 parts by weight, and dissolve this and the disproportionated rosin acid. An aqueous solution containing the same mole of sodium hydroxide dissolved therein was prepared at a weight ratio of 2:1 using a pressure pump, and the linear velocity at the tip was set at 250 per minute.
The milk was then continuously press-fitted into a colloid mill type emulsifier having a trapezoidal rotor rotating at 0 m.

The produced emulsion containing toluene was immediately sent to a toluene removal tank equipped with a heating jacket, and the toluene was evaporated off by heating.

At this time, some of the water evaporates together with toluene, resulting in a solid content of 50
．． A 6 weight percent block copolymer latex was obtained.

The mechanical stability of this product is 1200 seconds, and the MFT
No film was formed at room temperature at 65°C.

The film was formed at 100°C, and the tensile test results showed a maximum tensile strength of 184 kg/i1 elongation of 950%.

Reference Example 2 2.5 parts by weight of disproportionated rosin acid was added to a 33 weight percent toluene solution containing 100 parts by weight of butadiene-styrene-butadiene-styrene block copolymer rubber (molecular weight 70,000, bound styrene content 40 weight percent). and 25 parts by weight of polyoxyethylene nonylphenyl ether with a degree of polymerization of oxyethylene of 15, and further 2.0 parts by weight of a compound obtained by adding 100 parts by weight of ethylene oxide to 100 parts by weight of di(α-phenylethyl)phenol. This solution is mixed with an aqueous solution containing equimolar sodium hydroxide and disproportionated rosin acid.
They were mixed at a weight ratio of 2:1 and emulsified using a disver mill.

The toluene in the produced emulsion was removed by evaporation, and the solid content was reduced to 53.
A 2 weight percent block copolymer latex was obtained.

The mechanical stability of this product is over 1800 seconds, and M
FT was 67°C and no film was formed at room temperature.

Furthermore, a film is formed at 100℃ and has a maximum tensile strength of 165kg7c.
rit, and the elongation was 1100%.

Example 1 The block copolymer latex obtained in Reference Example 1, mesitylene (20 parts by weight per 100 parts by weight of the block copolymer) and formaldehyde condensate of di(α-phenylethynolyphenol) (average degree of polymerization 3) ) and a compound prepared by adding 300 parts by weight of ethylene oxide (2 parts by weight per 100 parts by weight of the block copolymer) were simultaneously mixed to obtain a block copolymer latex composition.

The mechanical stability of this composition was sufficiently stable for 1800 seconds or more, and the MFT was also below room temperature, forming a uniform transparent film at room temperature.

The tensile test results for this film showed a maximum tensile strength of 160k.
g/cIiL and elongation of 1000%, and had significantly improved film forming properties.

Example 2 A block copolymer latex composition was obtained in the same manner as in Example 1 except that the following solvents were used in different amounts in place of mesitylene used in Example 1.

The analysis and evaluation results of this product are shown in Table 1.

A) 20 parts by weight of n-decane block copolymer.

B) Same as above 10 parts by weight.

C) Same as above 30 parts by weight.

D) 2-ethylhexyl acetate 〃20 parts by weight.

E) Butyl butyrate 020 parts by weight.

F) 0-dichlorobenzene 〃20 parts by weight.

G) Same as above 〃 10 parts by weight.

H) 20 parts by weight of n-decane/toluene 50750 weight percent mixture.

■) Mesitylene/toluene 〃20 parts by weight.

J) 2-ethylhexyl acetate /Octane 〃 20 parts by weight.

Example 3 The following compound was used in the amount used in Example 1, in which 300 parts by weight of ethylene oxide was added to 100 parts by weight of the formaldehyde condensate of di(α-phenylethyl)phenol (average degree of polymerization 3). A block polymer latex composition was obtained in the same manner as in Example 1 except that the following were used.

The analysis and evaluation results are shown in Table 2.

A) 1.5 parts by weight of a compound obtained by adding 200 parts by weight of ethylene oxide to 100 parts by weight of a formaldehyde condensate of octylphenol (average degree of polymerization 5) B) 100 parts by weight of a formaldehyde condensate of nonylphenol (average degree of polymerization 3) 1.5 parts by weight of a compound to which 300 parts by weight of ethylene oxide was added C) Formaldehyde condensate of di(α-phenylethyl)phenol (average degree of polymerization 2) 200 parts by weight of ethylene oxide was added to 100 parts by weight 0.5 parts by weight of the compound D) 5 parts by weight of the same compound.

Comparative Example 1 Table 2 shows the analysis and evaluation results of the composition of Example 1 which does not contain the ethylene oxide adduct of the formaldehyde condensate.

Example 4 A composition was obtained in the same manner as in Example 1 except that the block copolymer latex obtained in Reference Example 1 used in Example 1 was replaced with the latex obtained in Reference Example 2.

The analytical evaluation results are shown in Table 1. Comparative Example 2 Table 2 shows the analytical evaluation results of the composition of Example 4 which does not contain the ethylene oxide adduct of the formaldehyde condensate.

Comparative Example 3 A composition was obtained in the same manner as in Example 1 except that the following solvent was used in place of mesitylene used in Example 1.

The analytical evaluation results are shown in Table 2.

A) 20 parts by weight of toluene B) 40 parts by weight of toluene C) 20 parts by weight of diacetone alcohol D) 20 parts by weight of carpitol E) 20 parts by weight of P-cresol As is clear from the above reference examples, working examples and comparative examples, this invention The block copolymer latex composition of the invention has sufficient mechanical stability, has an MFT of below room temperature, forms a uniform transparent film at room temperature, and can be heated without heat treatment or other treatment. It exhibited high strength and elongation, which are characteristics of plastic elastic materials.

Claims (1)

[Claims] 1) A) is 100 parts by weight of a block copolymer latex consisting of an aromatic vinyl compound and a conjugated diene compound; 2 to 20 parts by weight of the solvent used as a component, c) is a phenol (the following general formula (I)) ((R2)m Crtt)n + Σ0H (I) (where Ro is an aryl group, an aralkyl group, or a carbon number 8 to 18 alkyl group, R2 represents hydrogen or an alkyl group having 8 or less carbon atoms, n and m are integers of 1 to 3, n+m is 5 or less, and R1 when n or m is 2 or more Alternatively, R2 may be different from each other. 0.2 to 8 parts by weight of a compound obtained by adding ethylene oxide to the aldehyde condensate of )], and is characterized by comprising the above a))) A block copolymer latex composition with improved film-forming properties.