JPS59215346A - Vinylidene chloride latex - Google Patents

Abstract

PURPOSE:To provide the titled latex which gives a coating film having high barrier properties and excellent blocking resistance and adhesion, by mixing a vinylidene chloride latex having no film-forming properties with a vinylidene chloride latex having good film-forming properties. CONSTITUTION:90-99mol% of vinylidene chloride and 10-1mol% of an alpha,beta- ethylenically unsaturated carboxylic acid glycidyl ester are emulsion-polymerized to prepare a vinylidene chloride latex A having epoxy groups, a high vinylidene chloride content and no film-forming properties. Separately, 75-93mol% of vinylidene chloride and 25-3mol% of a cyanoalkene such as acrylonitrile are emulsion-polymerized to prepare a vinylidene chloride latex B having nitrile groups and good film-forming properties. The latex A is mixed with the latex B in a ratio of A/B of 20:80-60:40 on a solid basis to obtain the desired vinylidene chloride latex.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a vinylidene chloride resin latex that has both thermosetting and thermoplastic properties and provides a highly barrier coating film with excellent blocking resistance and good adhesion. It is something.

Vinylidene chloride latex has a coating film with excellent barrier properties, chemical resistance, etc., and is widely used in the food packaging field etc. by coating on plastic films and the like.

When coating vinylidene chloride-based tex on plastic films, etc., the coated and dried film is generally wound up into a roll, and the rolled film is stored. In addition, due to the adhesiveness of the coating film, a blocking phenomenon often occurs between the coating film surface and the base film surface, or between the coating film surfaces, and in this case, the smoothness of the coating film surface may be affected. The commercial value of the coated film may be significantly lowered due to lack of strength and transparency, and workability may be lowered, such as difficulty in feeding the film out of the roll.

In order to improve the above-mentioned drawbacks of vinylidene chloride-based latexes, it is known that it is effective to highly crystallize the coated film, and many methods have been proposed for this purpose. However, it has been found that all of these methods, which were effective in conventional coating methods, have completely unsatisfactory effects in recent new coating methods.

In other words, the present inventors recently applied a coating with vinylidene chloride-based latex by treating it at a previously unimaginable high temperature, higher than the melting point of vinylidene chloride homopolymer, and developed a coating that sufficiently progressed crystallization. It has been found that the coated film has much superior performance than the coated film made by conventionally known methods (JP-A-Sho S. Ku/l,!2!
;, Publication No. 3), even if attempts were made to avoid the blocking phenomenon by simply increasing the crystallization rate using conventionally proposed methods, in recent years coating processes that require higher speeds,
The coating film melted by high-temperature treatment cannot reach a sufficiently high degree of crystallinity again in a short period of time until it is wound up into a roll, resulting in an unsatisfactory effect.

In coating methods that involve high-temperature treatment that melts the coating film, simply increasing the crystallization rate using conventionally proposed methods does not allow the coating film to reach a sufficient degree of crystallinity. It has become clear that recrystallization takes a considerable amount of time and is unsatisfactory in avoiding blocking phenomena.

Therefore, the present inventors determined that the temperature at which the high-temperature treatment was completed.

Therefore, we have already investigated the possibility of developing a vinylidene chloride-based latex that can provide a coating film that is hard enough to prevent blocking.

Thermosetting resins are generally well known for providing coatings with high hardness through high-temperature treatment, and the general explanation is that their hardness is due to the regulation of molecular movement by crosslinking. .

However, the barrier property (impermeability) against oxygen and water vapor, which is the most important property of vinylidene chloride-based latex coatings, is due to the fact that the coatings are thermoplastic and therefore have crystallinity. Therefore, if the coating film is thermally crosslinked, it will remain fixed in an amorphous state and lose its crystallinity, making it no longer possible to expect barrier properties. That is, if the coating film is simply made thermosetting in order to avoid the blocking phenomenon, vinylidene chloride latex will lose its significance in the food packaging field.

Therefore, the present inventors have developed a vinylidene chloride-based latex that provides a coating film that has both high hardness due to thermal crosslinking and high crystallinity due to thermoplasticity. We have been considering ways to achieve these goals and have made proposals to date.

That is, patent application No. 37-60111. In the invention of No. 1, by curing the coating film by thermal crosslinking, it was possible to satisfactorily obtain a coating film with sufficiently excellent blocking resistance.

However, in applications where further printing is applied to the coating film made from this proposal or when other plastic films are laminated, there is dissatisfaction with the adhesion between the printing ink or laminating adhesive and the coating film. remained. If you try to improve adhesion, you have to lower the degree of curing,
It turned out that blocking resistance was sacrificed.

Therefore, the present inventors continued to conduct further studies to find a vinylidene chloride-based latex that has both good boot-king resistance and adhesion and provides a coating film with high barrier properties, and developed a latex containing epoxy groups. The present inventors have discovered that if a latex mixed with a latex containing a nitrile group is used, a coating film with satisfactory blocking resistance and adhesion and high barrier properties can be obtained, and the present invention has been accomplished.

That is, the present invention provides a vinylidene chloride latex (latex A) containing an epoxy group and having a high vinylidene chloride content and substantially no film forming properties, and a vinylidene chloride latex containing a nitrile group and having good film forming properties. system latex (Latex B) is mixed at a solid content ratio of 20:gO to 60:lIO to provide a coating film with good blocking resistance and adhesion and high barrier properties. This relates to vinylidene chloride latex.

Latex A as a preferred embodiment of the present invention is vinylidene chloride qONq? mol%, glycidyl ester lN of ethylenic α,β-unsaturated carboxylic acid 10 mol%, and monomers emulsion copolymerizable with them 0 to 10 mol%
It is a vinylidene chloride-based latex obtained by emulsion copolymerizing a mixture of (based on 10O of the co-species monomer), and in a preferred embodiment, latex B is vinylidene chloride 7
! This latex is obtained by emulsion copolymerizing a mixture consisting of a total of 700 mol% of r-93 mol%, cyanoalkene 3 to 23%, and monomers emulsion copolymerizable with these 0 to 22 mol%.

In addition, the epoxy group contained in latex A is derived from glycidyl acrylate or glycidyl methacrylate,
The nitrile group contained in latex B is preferably derived from acrylonitrile or methacrylatetrile.

The method for incorporating an epoxy group into latex A according to the present invention includes (a) an emulsion copolymer with a monomer mixture containing vinylidene chloride or vinylidene chloride; (b) A method of graft polymerizing a monomer having an epoxy group to a vinylidene chloride-based latex resin; (c)
There is a method of grafting a polymer compound containing an epoxy group to a vinylidene chloride-based latex resin.

(a) It has an epoxy group and emulsifies with vinylidene chloride.
゛Polymerizable monomers include ethylenic α,β-unsaturated carboxylic acids such as acrylic acid, methacrylic acid, itaconic acid, itaconic acid monoalkyl ether, or p-tonic acid, and glycide, methylglyside, dimethylglyside, etc. An ethylenically α,β-unsaturated acid ester consisting of an alcohol compound having an epoxy group, an ester consisting of an organic carboxylic acid compound having an epoxy group such as glycidic acid or methylglycidic acid, and an ethylenically unsaturated flucol such as allyl alcohol. Compounds glycide, methylglyside, dimethylglyside and bisphenol A
Examples include ether compounds consisting of an alcohol compound having an epoxy group such as monoglycidyl ether and an ethylenically unsaturated alcohol such as allyl alcohol. These monomers may be premixed with other raw material monomers such as vinylidene chloride for emulsion copolymerization, or may be added separately from other monomers and emulsion copolymerized before or during emulsion polymerization. good.

In the method of ←), the seven polymers listed in (a) can be used, and are added to vinylidene chloride latex for graft polymerization.

(For sea urchin, there is a method in which a homopolymer or copolymer of the monomers listed in (a) is grafted onto a vinylidene chloride-based latex resin by a polymer reaction.

In addition, in order to make latex B contain a nitrile group,
A method of emulsion copolymerizing an ethylenically based α,β-unsaturated carboxylic acid ester having a cyano group such as cyanoalkene such as acrylnitrile or methacrylnitrile, cyanoethyl acrylate, or cyanoethylmethacrylate with vinylidene chloride; - a method of graft polymerizing vinylidene chloride-based latex resin;
There is a method of grafting a polymer compound having a nitrile group onto a vinylidene chloride latex resin.

The monomers capable of emulsion copolymerization in latex A and latex B of the present invention include ethylenic α,β-unsaturated carboxylic acids such as acrylic acid, methacrylic acid, or itaconic acid, alkyl esters or hydroxyalkyl esters of these unsaturated carboxylic acids. Ethylene α such as esters and acrylamide.

There are amide compounds of β-unsaturated carboxylic acids, vinyl chloride, vinyl esters such as vinyl acetate, vinyl ethers such as vinyl methyl ether, allyl esters such as allyl acetate, allyl ethers such as allyl methyl ether, and latex B contains 7-crylonitrile. Alternatively, a cyanoalkene such as methacrylnitrile or an ethylenic α,β-unsaturated carboxylic acid ester having a cyano group such as cyanoethyl acrylate can also be used.

In addition, catalysts for emulsion copolymerization include persulfates such as sodium persulfate, hydrogen peroxide, and water-soluble organic peroxides such as tertiary nitrate oxide.
Part or all of the catalyst is added before or during the polymerization.

Further, a reducing agent such as sodium hydrogen sulfite or Rongalit can be used as a cocatalyst.

Surfactants for emulsion copolymerization and for adjusting the gas-liquid surface tension of latex include alkyl sulfonic acid sodium salts, alkylbenzenesulfonic acid sodium salts, alkyldiphenyl ether disulfonic acid sodium salts, higher alcohol sulfate ester sodium salts, polyoxy Examples include ethylene alkylphenyl ether sulfonic acid sodium salt, polyoxyethylene alkyl ether, polyoxyethylene alkylphenyl ether, and polyoxyethylene alkyl ester.

The composition ratio of vinylidene chloride in latex A of the present invention is 90
If it is less than mol%, the desired blocking resistance cannot be obtained. In addition, if it exceeds Tademol%, the content of glycidyl ester of ethylenically α,β-unsaturated carboxylic acid will be less than 1 mol%, which will also make it impossible to secure the desired blocking resistance and improve adhesive properties. will no longer be satisfactory.

Moreover, if the content of the glycidyl ester exceeds 70 mol%, the content of vinylidene chloride will fall below 90 mol%, making it impossible to ensure desired blocking resistance.

In the latex A of the present invention, other hexamers can be used in conjunction with vinylidene chloride and the glycidyl ester as desired, but the amount (mol%) thereof is determined in such a manner that the desired high degree of blocking resistance is not achieved. , the amount (mol %) of the glycidyl ester should not be exceeded.

The composition ratio of vinylidene chloride in latex B of the present invention is 7S.
If it is less than 93 mol %, the barrier property, which is the basic performance, will not be satisfactory, and if it is 93 mol % or more, the desired film forming property will not be obtained.

Furthermore, if the composition ratio of cyanoalkene referred to in latex B of the present invention is less than 3 mol%, the desired blocking resistance cannot be obtained, and if it exceeds 25 mol%, vinylidene chloride
Therefore, the object of the invention will not be achieved as described above.

The mixing ratio of latex A and latex B of the present invention is 20:go to 60:θ in terms of solid content ratio. Latex A
If the amount is less than this, the boot-king resistance will not be satisfied, and if it is too large, the film forming properties will be poor and a good coating film will not be obtained.

The present invention will be described in detail below with reference to examples. Parts or ``chi'' and ``■'' refer to parts by weight or % by weight.

Example/ Latex A and latex B were obtained by each method below.

Latex A Water grated in a glass-lined pressure reactor 1 Sodium alkyl sulfonate (Bayer Mep-Solate H9
Same hereafter) OaS part and sodium persulfate O, OS
After degassing, the temperature of the contents was maintained at 20°C. In another container, vinylidene chloride (VDC”) 91
17 parts of glycidyl methacrylate (GMA) and 07 parts of acrylic acid (AA) were weighed and mixed to prepare a 7-mer mixture. 7 of the seven-mer mixture in the reactor
0 parts was charged, and the reaction was allowed to proceed with stirring. After confirming that the reaction had progressed sufficiently by decreasing the internal pressure in the reactor, the aqueous solution of sodium flukylsulfonate was added. r,s
(8 parts of 0g as an active ingredient) was then press-injected, and then the remaining entire amount of the squeezed monomer mixture was press-injected at once. Furthermore, S
A 1% aqueous solution of sodium alkylsulfonate/part A (0 g part as an active ingredient) was continuously pressurized in fixed amounts over 20 hours. The other day! The reaction was allowed to proceed until the internal pressure was sufficiently lowered. An aqueous solution of sodium flukylsulfonate was added to the latex thus obtained to adjust the gas-liquid surface tension at 20° C. to 1I codyne/crn.

The composition ratio of the monomer mixture charged in this latex is as follows when expressed in mol%.

Vl) C97 mol% GMA 2 mol% AA 1 mol% For the resin obtained by coagulating this latex in warm methanol and drying, the chlorine content determined by Sht5niger's oxygen flask combustion method was 7037%, When converted to vinylidene chloride content, it was 1-/H.

In addition, for the gas produced by thermally decomposing the same resin, the amount of λ, 3-trick, p, and ppan was determined using a gas chromatogram, and the amount of gas generated was determined using a gas column graph.
, 2. ,? -) The content of glycidyl methacrylate was determined to be 3.06% based on the calibration curve showing the relationship between the weight of lychlorpropane and the weight of glycidyl methacrylate.
Met.

The amount of acrylic acid was determined to be 073% by subtracting the amount of vinylidene chloride and the amount of glycidyl methacrylate. When this is converted into mol%, it becomes 949 mol% of VDC, 21 mol% of GMA, and 70 mol% of AA, and it is considered that substantially the entire amount of the monomers charged has become a polymer.

Latex B In a pressure-resistant reactor with glass lining, 16 parts of water,
Alkyl sulfonic acid sodium O/left part and sodium persulfate O, is part were charged, and after deaeration, the temperature of the contents was maintained at 55°C. In a separate container, ■917 parts of DC,
3.7 parts of acrylonitrile (AN) and methyl acrylate (MA) were weighed and mixed to prepare a seven-mer mixture. In the reactor, io
The reaction was allowed to proceed under stirring. After confirming that the reaction had mostly progressed by lowering the internal pressure of the reactor, 10 parts of a 15% aqueous solution of sodium flukylsulfonate (13 parts as the active ingredient) was injected into the reactor, and the remaining hindlimb monomer mixture was removed. The entire amount was continuously and quantitatively injected over 70 hours. The reaction was further continued until the internal pressure was sufficiently lowered. A 75% aqueous solution of sodium flukylsulfonate was added to the latex thus obtained so that the gas-liquid surface tension at 20° C. was 912 dyne/cm.

The composition ratio of the monomer mixture charged in this latex, expressed in mol%, is as follows: 0 VDC 11 mol% AN ff mol% MA Damol% The content was 9163%, and when the nitrogen content was determined by the Miku μ Kjeldahl method and converted to the acrinitrile content, it was a little over 63%.

The amount of methyl acrylate was determined to be 27y parts by subtracting the amount of vinylidene chloride and the amount of 7-crionitrile. When this is converted into mol%, it becomes VDC 177 mol% AN & 1 mol% MA 'AO mol%, and it is considered that substantially the entire amount of the charged 1000 molar mass has become a polymer.

Latex A and latex B were mixed at a predetermined ratio to obtain the latex referred to in the present invention.

The dry coating amount of the latex on a coaxially stretched knife film (/Sμ) is ! Coating so that t f/mt, g
It was dried for 3 seconds in an open oven maintained at θ°C. Thereafter, the mixture was placed between molds to prevent thermal shrinkage and heated for 6 seconds in an open chamber kept at 200°C, and then cooled to room temperature by blowing cold air to obtain a coated product. This coated product was evaluated for blocking resistance, adhesion, and barrier properties as referred to in the present invention as described below.

That is, immediately after cooling, the coated product was stacked so that the coated surface and the base material surface were in contact with each other, and a pressure of 2 kg/crl was applied thereto, and the coated product was left in an open environment at 10° C. for 20 hours.

Thereafter, the film was peeled off and the coated surface was observed to determine blocking resistance. Those with no traces of crimping were marked with ◎, those with slight traces with ○, and those with strong traces with X.

Adhesion as referred to in the present invention can be evaluated by the adhesion of printing ink to a coated object. That is, after the coated product was aged for 2 days in an oven kept at 0°C, GNC-8TN white ink (manufactured by Toyo Ink) was applied on the coated film surface for a dry coating amount of 22 hours. It was coated and dried for 7 minutes in an oven kept at 60°C. Thereafter, an ink cellophane peel test was conducted to determine ink adhesion. Those with no peeling at all are marked with ◎, those with almost no peeling are marked with ○, and those with obvious peeling are marked with X.

In addition, after aging the coated product for 2 days in an oven maintained at lIO°C, OXTRAN −/00 (M
Oxygen permeability was measured at 20[deg.] C. and relative humidity l[theta][chi] using a microcomputer (manufactured by OdernControl). Measured values are cc/, l.

Expressed in units of atm-2 dahr.

Blend latexes in which the mixing ratio of latex A and latex B was between 0 to 60 and 60 to 0 showed satisfactory results in blocking resistance, adhesion, and barrier properties; The blocking resistance was poor, and at a mixing ratio of 70:30, satisfactory barrier properties could not be obtained, probably due to poor film formability.

These results are shown in Table 1.

Comparative Example / Latex A does not contain the glycidyl ester of the present invention and is a monomer mixture consisting of 97 mol% vinylidene chloride and 3 mol% methyl acrylate.
The latex A obtained in exactly the same manner as the latex A of
and Latex B, which is the same as in Example/, were mixed in a predetermined ratio, and coating was carried out in the same manner as in Example/, including treatment at high temperature, to obtain a coated product. This coated product was evaluated for blocking resistance and adhesion. As shown in Table 7, both performances were unsatisfactory.

Unless otherwise specified, the examples shown below differed from Example 1 only in the composition of the seven-mer mixture, and all the latex and coating preparation and evaluation methods were the same as in Example 2. However, for those with poor blocking resistance, the barrier properties were no longer measured. The results are summarized in Table 7.

Comparative Example λ Latex A was the same as in Example 1, and latex B contained 0 mol of vinylidene chloride, 3 mol% of methyl acrylate, and no cyanoalkene of the present invention.
and 2 mol % of methacrylic acid (MAA).

Example λ Latex A was obtained from a monomer mixture consisting of 95 mol% vinylidene chloride and 5 mol% glycidyl methacrylate. Vinylidene chloride gmol%, acrylonitrile gmol%, and methyl methacrylate (HMA')
Latex B was obtained from a monomer mixture consisting of 1 mol %.

Example 3 Latex A was the same as in Example -, and latex B was made of 90 mol% vinylidene chloride and methacrylnitrile (
It was obtained from a monomer mixture consisting of 3 mol % of MAN ) A and 3 mol % of methyl acrylate.

Example Gratex A contains vinylidene chloride q4' mol%, glycidyl methacrylate gumol%, and methacrylic e2
It was obtained from a monomer mixture consisting of mol %. Latex B
The same one as in Example was used.

Example S Latex A was made from a monomer mixture consisting of 91 mole percent vinylidene chloride, 7 mole percent glycidyl methacrylate, and co mole percent methyl methacrylate.

Latex B was the same as in Example.

Comparative Example 3 Latex A was prepared from a monomer mixture consisting of gIr mol% vinylidene chloride below the lower limit of the present invention, glycidyl methacrylate gmol%, methyl acrylate 6 mol%, and methacrylic acid 2 mol%. Latex B was the same as in Example 1.

Example 6 Latex A was the same as in Example.

Latex B was made from a monomer mixture consisting of gO mole % vinylidene chloride and θ mole % methacrylonitrile.

The above results are summarized in Table 1.

(Leaving space below) Procedural amendment (spontaneous) July 25, 1980 Mr. Kazuo Wakasugi, Commissioner of the Patent Office ■, Indication of case Patent Application No. 89225, 1989 2,
Name of the invention: Vinylidene chloride latex 3. Relationship with the person making the amendment: Patent applicant: 1-2-6 Dojimahama, Kita-ku, Osaka-shi, Osaka (003) Asahi Kasei Industries, Ltd. Representative Director and President Teru Miyazaki 4, Agent 3-7 Yotsuya, Shinjuku-ku, Tokyo, New Building 586, the statement in the description of the contents of the amendment in the "Scope of Claims" and "Detailed Description of the Invention" columns of the specification to be amended is amended as follows.

(The scope of claim 11 is amended as shown in the attached sheet.

(2) On page 7, lines 14 to 16, "and a mixture of monomers capable of emulsion copolymerization with them" was replaced with "and a monomer capable of emulsion copolymerization with the above two monomers with 0
~10 mol%, for a total of 100 mol%.''

(3) “ether” on page 8, line 20 “Esther,” I corrected.

(4) Correct "Latex B" in line 4 of page 11 to "Latex A."

Patent Applicant: Asahi Kasei Industries Co., Ltd. Agent Patent Attorney: Toru Hoshino Scope of Patent Claims (1) Vinylidene chloride-based latex containing epoxy groups, having virtually no film-forming properties, and having a high vinylidene chloride content (Latex A) and vinylidene chloride-based latex (latex B) containing nitrile groups and having good film-forming properties.
A vinylidene chloride-based latex which provides a coating film with good blocking resistance and adhesion and high barrier properties, characterized in that the following are mixed in a solid content ratio of 20:80 to 60:40.

(2) Latex A is vinylidene chloride 90-99
A mixture of 1 to 10 mol% of glycidyl ester of ethylenically based α,β-unsaturated carboxylic acid and 0 to 10 mol% of a monomer that can be emulsion copolymerized with the above two monomers was emulsion polymerized. Latex B is vinylidene chloride 75-93
A total of 100 mol%, 3 to 25 mol% of cyanoalkenes, and 0 to 22 mol% of monomers emulsion copolymerizable with them.
The vinylidene chloride-based latex according to claim 1, which is a latex obtained by emulsion polymerization of a mixture consisting of mol%.

(3) The vinylidene chloride latex according to claim 1 or 2, wherein the epoxy group is derived from glycidyl acrylate or glycidyl methacrylate, and the nitrile group is derived from acrylonitrile or methacrylonitrile.

Patent applicant: Asahi Kasei Industries, Ltd. Agent: Patent Attorney Toru Hoshino

Claims (3)

[Claims] (1) Contains an epoxy group and has virtually no film-forming properties;
A vinylidene chloride-based latex (latex A) with a high vinylidene chloride content and a vinylidene chloride-based latex (latex B) containing a nitrile group and having good film-forming properties have a solid content ratio of θ to g. ~60 to 11. characterized by being mixed with O,
A vinylidene chloride latex that provides a coating film with good blocking resistance and adhesion and high barrier properties. (2) Latex A contains 90-97 mol% of vinylidene chloride, glycidyl ester of ethylenically based α,β-unsaturated carboxylic acid/-10 mol%, and θ to 10 mol% of the above comonomer based on the total amount lOO of the above comonomers. It is a latex formed by emulsion polymerization of a mixture of a monomer and a heptamer that can be emulsion copolymerized, and latex B is vinylidene chloride'.
7! -93 mol%, cyanoalkene 3-2 mol%,
and monomer ON21 mol% which can be emulsion copolymerized with them.
The vinylidene chloride latex according to claim 1, which is a latex obtained by emulsion polymerization of a mixture consisting of a total of 700 mol%. (3) The vinylidene chloride latex according to claim 1 or 2, wherein the epoxy group is derived from glycidyl acrylate or glycidyl methacrylate, and the nitrile group is derived from acrylonitrile or methacrylonitrile.