JPS63297407A - Manufacture of emulsion - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention provides an improved vinyl acetate-ethylene copolymer.
Regarding emulsions and their manufacturing methods.

More particularly, the present invention relates to a process for making vinyl acetate-ethylene copolymer emulsions having improved thickening response, improved storage stability, and improved adhesion and creep resistance.

(Prior Art) Polymer emulsions containing vinyl acetate-ethylene copolymers and protective colloids are used when bonding porous materials such as wood, cloth, and paper to each other, or when bonding these to polyvinyl chloride films, polystyrene films, and polyester films. It provides excellent adhesive strength when bonding to non-porous materials such as polyethylene films, making it particularly suitable as an adhesive.

These emulsions are widely used in the adhesive industry because they offer important advantages such as ease of formulation for the adhesive user and relatively low cost. Although technology has developed significantly over the years, both with regard to its manufacture and its end use, commercially available vinyl acetate-ethylene copolymer emulsions as adhesives still have unresolved drawbacks. Until now, it has not been possible to combine various desirable properties such as good storage stability and thickening response with excellent peel strength and creep resistance in one vinyl acetate-ethylene copolymer emulsion. Ta.

Creep resistance is the resistance to slow displacement, elongation or displacement of the adhesive interlayer at the bonded or laminated surfaces, especially at high temperatures at which the displacement occurs. This slow displacement eventually leads to adhesive failure. As used herein, the term "creep resistance" refers to such resistance to displacement or elongation of the adhesive interlayer. In fact, adhesives that exhibit creep resistance are also those that exhibit peel resistance.

Laminated structures are often subjected to fairly high stresses;
Easy to cause delamination. An adhesive intermediate layer that exhibits resistance to such peeling properties can be said to have good peel strength.

As used herein, the term "peel strength" refers to resistance to such peeling.

With respect to vinyl acetate-ethylene emulsions, the term "thickening response" as used herein means the ability of the emulsion to be thickened by the addition of a solvent or plasticizer. This property is a very important property for adhesive emulsions. These properties allow adhesive users to add relatively inexpensive solvents such as toluene to the emulsion, allowing them to remain on the surface of porous substrates such as wood and paper without penetrating into the material. This is because it is possible to obtain a "ready-to-use" adhesive that can be used in a variety of applications. With such properties, there is no need to use expensive thickeners. The thickening response of the emulsion is measured by the thickening response test.

The storage stability of vinyl acetate-ethylene copolymer 0 emulsions is of great importance to adhesive users, especially when emulsion containers must be stored for long periods of time during distribution and distribution processes. Internal temperatures in warehouses and transportation vehicles are often very high, further exacerbating this storage problem. In fact, poor storage stability of an emulsion results in a decrease in solids content and emulsion viscosity in the upper layer of the emulsion in a non-stirable container, whereas an increase in solids content and viscosity in the lower layer of the container. As a result, adhesive users cannot use the emulsion unless they can stir it, which is often impossible.

The storage stability of emulsions is determined by the dilution precipitation test. As used herein, the term "storage stable" indicates that the emulsion separates into two or more layers in the container during storage.

Polymeric emulditanes containing protective colloids along with vinyl acetate-ethylene copolymers are well known in the art. Many problems associated with the manufacture and use of these emulsions are discussed in various patent documents, including the following: U.S. Pat. No. 3,708,388 discloses an adhesive composition comprising a vinyl acetate-ethylene copolymer emulsion containing 5 to 40% by weight of ethylene, in which vinyl acetate and ethylene are copolymerized in the presence of a protective colloid such as polyvinyl alcohol or hydroxyethyl cellulose. is disclosed. In the examples of this patent, the amount of protective colloid is limited to 2% by weight of the emulsion. U.S. Pat. No. 4,043,961 discloses an adhesive composition containing a vinyl acetate-ethylene copolymer, in which a special vinyl alcohol-methyl methacrylate copolymer is used as a protective colloid to obtain an adhesive with good water resistance. It states that it will be done. This patent does not teach how to obtain good storage stability and thickening response properties of the emulsion.

U.S. Pat. No. 3,661,696 discloses an adhesive composition with improved adhesion to plastic films containing a vinyl acetate-ethylene copolymer, where the vinyl acetate and ethylene are copolymerized in the presence of a seed emulsion. . This patent does not teach anything about improving the thickening response of emulsions. U.S. Pat. No. 3,769,151 discloses vinyl acetate-ethylene copolymer-containing adhesive compositions with improved thickening response, in which vinyl acetate and ethylene are combined with fully and partially hydrolyzed grades of polyvinyl alcohol mixtures, It is copolymerized in the presence of a saturated carboxylic acid and a seed polymer. There is no teaching in this patent how to obtain better storage stability and creep resistance along with better thickening response. U.S. Pat. No. 4,267,090 discloses that vinyl acetate and ethylene are combined in amounts ranging from 1 to 1, based on the total weight of polyvinyl alcohol and monomer.
A vinyl acetate-ethylene latex having excellent vinyl wetting properties and sufficient creep resistance copolymerized in the presence of 2% by weight wetting agent is disclosed. This patent does not teach anything about thickening response and storage stability.

SUMMARY OF THE INVENTION The present invention is a method for producing aqueous vinyl acetate-ethylene copolymer emulsions, the emulsions obtained exhibiting excellent performance in thickening response tests and dilution precipitation tests, and containing 5 to 40% by weight and at least one emulsifier having an ethylene content of 0.5% by weight or less of the total weight of the emulsion and a protective colloid of 2.0% or more but not more than 5.0% by weight of the total weight of the emulsion (the protective colloid being substantially (a copolymer of vinyl acetate and vinyl alcohol, the average vinyl acetate content of which is 11 to 14 mol %).

Vinyl acetate-ethylene copolymer emulsions consist of a vinyl acetate-ethylene copolymer dispersed in an aqueous medium, with the presence of a small amount of a surfactant and a relatively large amount of partially hydrolyzed polyvinyl alcohol or a mixture of said partially hydrolyzed polyvinyl alcohols. It is produced by emulsion polymerization of vinyl acetate and ethylene. The resulting emulsion is particularly suitable for use in adhesive applications due to its good balance of properties.

(The detailed description provides a method for making a vinyl acetate-ethylene copolymer aqueous emulsion.

The copolymer contains 5-40% by weight of ethylene and 60-40% by weight of ethylene.
Contains 95% by weight vinyl acetate. Preferably, the copolymer comprises 5-25% by weight ethylene and 75-95% by weight vinyl acetate and has a glass transition temperature (Tg) of -15%.
~+25°C. Other vinyl monomers can also be included in the polymerization process. Other vinyl monomers can also be used, such as, for example, vinyl formate, vinyl propionate, vinyl versatate, vinyl laurate, vinyl stearate. Other olefins such as propylene, isobutylene and other higher alkyl alpha-olefins, and mixtures thereof, may also be used with ethylene or by themselves. Addition of small amounts of acrylic esters, such as ethyl acrylate, butyl acrylate and 2-ethylhexyl acrylate, or maleic acid and fumaric esters, such as butyl maleic acid or fumarate, di-2-ethylhexyl maleic acid or fumarate, to the monomer mixture. can impart specific properties to emulsion polymers. Ethylenically unsaturated acid monomers are often used to produce copolymers with improved adhesion to certain surfaces, such as metal foils.
added to the monomer mixture. Generally, any ethylenically unsaturated mono- or dicarboxylic acid can be used to impart carboxyl functionality to the copolymer. Examples of suitable acids include monocarboxylic ethylenically unsaturated acids such as acrylic acid, crotonic acid and methacrylic acid; dicarboxylic ethylenically unsaturated acids such as maleic acid, fumaric acid, itanconic acid and citraconic acid;
Also included are half esters of these dicarboxylic acids and alcohols having 1 to 12 carbon atoms. These half esters include monomethyl maleate, monoethyl maleate, monobutyl maleate, mono(2-ethylhexyl) maleate, and the like. Alkali salts, ammonium salts and other metal salts of the carboxylic acids mentioned above can also be used. Ethylenically unsaturated sulfonic acids or salts thereof can be used to impart mechanical stability to the emulsion and to impart increased specific adhesion to the copolymer. Examples of suitable sulfonic acids and their salts are vinylsulfonic acid, allylsulfonic acid, 2-acrylamido-methylpropanesulfonic acid, etc. and their alkali, ammonium and other salts. Generally, 0°5~5%
using acids or salts.

Latent or active crosslinkers are often used to crosslink copolymers. As used herein, the term "latent crosslinkable monomer" refers to a part of the functionality that participates in copolymerization with other monomers, while the remaining functionality often undergoes subsequent copolymerization in the presence of a catalyst or by radiation. It refers to polyfunctional monomers which, upon drying and curing, cause crosslinking of the copolymer. Potentially crosslinking monomers are
For example, N-alkylolamides of α, β ethylenically unsaturated carboxylic acids having 4 to 10 carbon atoms, such as N-methylolacrylamide, N-ethanolacrylamide, N-
Proper tool acrylamide, N-methylolmethacrylamide, N-ethanolmethacrylamide, N~methylolmaleimide, N-methylolmaleamide, N-methylolmaleic acid, N-methylolmaleic acid ester; N-alkyl of vinyl aromatic acid Rollamides, such as N-methylol-p-vinylbenzamide; N-
(Alkoxymethyl)acrylates and methacrylates, the alkyl group having 1 to 8 carbon atoms. ], for example, N-(methoxymethyl)acrylamide, N-(butoxymethyl)acrylamide, N-(methoxymethyl)methacrylamide and N-(butoxymethyl)methacrylamide.

Also, mixtures of acrylamide, methacrylamide or allyl carbamates can be used with the latent crosslinking monomers described above. Other monomers in this category are N-methylolallyl carbamate, and N-(alkoxymethyl)allyl carbamate, where the alkyl group has 1 to 8 carbon atoms. ], for example N-(butoxymethyl)allyl carbamate and N-
(methoxymethyl)allyl carbamate, and mixtures of these monomers with allyl carbamate, acrylamide or methacrylamide. Epoxy-containing monoethylenically unsaturated compounds, such as glycidyl acrylate, glycidyl methacrylate and vinyl glycidyl ether, can be catalyzed with alkaline catalysts such as potassium carbonate, sodium carbonate, diethylenetriamine, etc. It functions as a potential cross-linking monomer by binding with sexually unsaturated carboxylic acids. hydroxyethyl acrylate,
Hydroxypropyl acrylate and the corresponding methacrylic ester exhibit latent crosslinking properties when bonded with an N-alkylolamide of an α-1β-ethylenically unsaturated acid having 4 to 10 carbon atoms or with the acid itself through ester formation. do. Another group of potentially crosslinking monomers is disclosed in U.S. Pat.
No. 8098 and No. 4009314.

These are of the formula: [wherein R is methyl or H, A is alkylene, and X and Y are halogen. ] It is a cationic chlorohydrin compound shown as follows.

The crosslinking reaction of these monomers is also catalyzed by the alkaline compounds mentioned above. The amount of latent crosslinking monomer in the copolymers of the present invention is approximately 0.00% of the copolymer.
5-10% by weight, preferably about 2-6% by weight.

As used herein, the term "active crosslinking monomer" refers to a multifunctional monomer that crosslinks the polymer composition during its initial formation. No subsequent drying or other curing techniques are required. This type of monomer is well known and contains 2 to 5 ethylenically unsaturated groups in one molecule separated by ester groups, ether groups, aromatic ring structures or nitrogen-containing ring structures (the unsaturated groups are addition polymerization can be carried out by free radical means). Suitable active crosslinking monomers include alkylene glycol diacrylates and dimethacrylates (e.g. ethylene glycol diacrylate), 1.3
-butylene glycol diacrylate, propylene glycol diacrylate, triethylene glycol dimethacrylate, etc., 1.3-glycerol dimethacrylate, l.

1, l-) Limethylolpropane dimethacrylate, 1
．． 1.1-trimethylolethane diacrylate, pentaerythritol trimethacrylate, sorbitol pentamethacrylate, methylenebisacrylamide, methylenebismethacrylamide, divinylbenzene, vinyl methacrylate, vinyl crotonate, vinyl acrylate, divinyl adipate: di- and triaryl Compounds such as triallyl cyanurate, triallyl isocyanurate, diallyl phthalate, allyl methacrylate, allyl acrylate, diallyl maleate, diallyl fumarate, diallyl idaconate,
Diallyl malonate, diallyl carbonate, triallyl citrate, triallyl aconitate; divinyl ether, ethylene glycol divinyl ether, and the like are included. The amount of active crosslinking monomer in the copolymers of the present invention is about 0,01 to 1.0%, preferably about 0.05 to 0.5% by weight of the copolymer.

The polymer emulsions of the present invention are prepared in the presence of suitable protective colloids such as polyvinyl alcohol, starch, dextrin, hydroxyethylcellulose, polyvinylpyrrolidone, and the like. Polyvinyl alcohol is particularly suitable for making emulsions according to the invention. Although there are a variety of braided polyvinyl alcohols available commercially, the partially hydrolyzed braided version is particularly suitable for the vinyl acetate-ethylene copolymer emulsilone preparation of the present invention. Partially hydrolyzed braided polyvinyl alcohol is produced by controlled hydrolysis of polyvinyl acetate. For information on these and other polyvinyl alcohols in commercially available braid, and their manufacture, please refer to the Encyclopedia for Polymer Science and Technology.
mer 5science and Technology.

gy, Wiley) New York 1971 vol. 14 15
4-157]. The amount of polyvinyl alcohol used in the polymer emulsion of the present invention is
It is 2.0 to 5.0% by weight, preferably 2.5 to 5% by weight, based on the total weight of the emulsion. If the amount of polyvinyl alcohol is less than 2%, the emulsion cannot be stored stably. Often, the viscosity of the top layer of the emulsion in the container will be less than 50% of the initial viscosity after a storage period of 6 months. The solid content of the upper layer of the emulsion in the storage container also
It is also often much lower than the original solids content.

Conversely, the solids content of the lower layer in the storage container will be much higher than the original viscosity and solids content of the emulsion. Separation of such emulsions makes their formulation difficult;
highly undesirable. Storage stability can be measured by the precipitate produced when the emulsion is diluted and allowed to stand for several days; this precipitate is referred to as a "dilute precipitate." Dilute precipitation and the storage stability exhibited thereby can be determined by a dilution precipitation test.

Generally, the dilute precipitate should not be more than 1.1, preferably no more than 1, as shown in this test. The test is described in detail in Example 7.

If more than 5% by weight of polyvinyl alcohol is used in the vinyl acetate-ethylene copolymer emulsilone of the present invention, the viscosity of the resulting emulsion becomes too high.

Although the use of low molecular weight braided polyvinyl alcohol reduces the viscosity of the emulsion, the use of such braided polyvinyl alcohol does not result in a cobolymer emulsion with sufficient peel strength when applied as a lamination adhesive. So it's not beneficial at all.

To modify the balance of properties such as degree of hydrolysis and molecular weight, and to obtain optimal emulsification, agent properties and viscosity, it is often advantageous to mix two or more different braids of polyvinyl alcohol. . Precise blending of polyvinyl alcohol also improves the grafting reaction of vinyl acetate to polyvinyl alcohol. The amount of graft polymer in the vinyl acetate-ethylene copolymer emulsion of the present invention determines the creep resistance and peel adhesion properties as well as the thickening factor of the polymer.

The amount of grafted polymer is between 25 and 50% by weight of the dry polymer, as determined by the benzene insolubility test;
Preferably it should be between 25 and 40% by weight. It is known that when vinyl acetate is polymerized in the presence of polyvinyl alcohol, the vinyl acetate undergoes a graft reaction to become polyvinyl alcohol. [For example, encyclopedia
Encyclopedia for Polymer Science and Technology, Willi (Encyclopedia for Po)
lymer 5science and Technology
ogyjiley) New York 1971 vol. 15 59
See page 4].

As mentioned above, the grafting reaction between polyvinyl alcohol and vinyl acetate imparts very useful properties to the vinyl acetate-ethylene copolymer emulsion containing polyvinyl alcohol.

For example, a high degree of grafting of vinyl acetate to polyvinyl alcohol significantly reduces the creep rate at elevated temperatures, a measure of the thermoplasticity of the copolymer, and also reduces the peel strength of laminates formed from the copolymer. will increase significantly. This also affects the so-called "thickening factor", which is a measure of the increase in emulsion viscosity, thereby
Better adhesion is obtained if plasticizers and/or solvents are added to the emulsion during the subsequent adhesive compounding step. The thickening factor of the emulsion of the present invention is:
Must be greater than 8 as determined by the thickening response test described in Example 7.

In order to obtain high grafting efficiency, it is important to optimize the balance between the degree of hydrolysis and molecular weight of the polyvinyl alcohol and its usage in the vinyl acetate-ethylene copolymers and emulsions of the present invention. The molecular weight of polyvinyl alcohol is indirectly indicated as the viscosity of a 4% polyvinyl alcohol solution, and the higher the viscosity of the 4% solution, the higher its molecular weight [Regarding polyvinyl alcohol, the correlation between the viscosity of a 4% solution and the molecular weight] Encyclopedia for Polymer Science
Encyclope
dia for Polymer 5science a
nd Technol.

gy, Wiley) New York 1971 vol. 14 15
See page 8. High molecular weight polyvinyl alcohol enhances grafting reactions, thereby providing beneficial properties for emulsion polymers as described above.

The degree of hydrolysis of polyvinyl alcohol is a measure of the acetate residues of polyvinyl alcohol, which are the main sites for the grafting reaction, the more acetate groups remain on the polyvinyl alcohol, the higher the degree of grafting reaction. Become.

The higher the degree of hydrolysis of polyvinyl alcohol, the lower the acetate content of polyvinyl alcohol and the lower the degree of grafting reaction. For example, if polyvinyl alcohol is hydrolyzed to 99 mol%, the acetate group content of polyvinyl alcohol is only 1%. On the other hand,
If the degree of hydrolysis is 86 mol%, the acetate content is 1
It is 4 mol%.

The mixture of polyvinyl alcohols and their amounts used in the present invention are carefully selected to provide maximum grafting with acceptable emulsion viscosity and emulsion stability. The degree of hydrolysis of the polyvinyl alcohol or mixture thereof useful in the vinyl acetate-ethylene copolymer φ emulsion of the present invention should be between 80 and 90 mol%, preferably between 86 and 89 mol%.

The molecular weight of the polyvinyl alcohol or mixture thereof is 3 to 70 cps, preferably 8 to 40 cps when expressed as a 4% solution viscosity of the polyvinyl alcohol or mixture thereof.
Must be s.

The vinyl acetate-ethylene copolymers of the invention, emulsions, are advantageously prepared in the presence of small amounts of emulsifiers, such as anionic, cationic, nonionic or mixtures thereof. However, it is also possible not to use emulsifiers at all. As a suitable nonionic emulsifier, 10 to
Alkylphenoxy polyethoxyethanols having 60, preferably 10 to 30 oxyethylene units and alkyl groups of about 7 to 18 carbon atoms, such as octylphenoxy polyethoxyethanol, methyloctylphenoxy polyethoxyethanol , nonylphenoxy polyethoxyethanol, dodecylphenoxy polyethoxyethanol; ethylene oxide derivatives of long chain carboxylic acids such as lauric acid, myristic acid, palmitic acid and stearic acid with 10 to 60 oxyethylene units per molecule. ; ethylene oxide derivatives of etherified or esterified polyhydroxy compounds with hydrophobic moieties such as lauric acid, myristic acid, valmitic acid and stearic acid, octyl, decyl, with 10 to 60 oxyethylene units per molecule; similar ethylene oxide condensates of long chain alcohols such as lauryl, stearyl, cetyl alcohol; etherified or esterified polyhydroxy with hydrophobic hydrocarbon chains such as sorbitan monostearate with 10 to 60 oxyethylene units; Ethylene oxide derivatives of compounds, octyl, decyl, lauryl,
Long chain alcohols such as stearyl and cetyl alcohol,
Similar ethylene oxide condensates; include block copolymers of ethylene oxide and propylene oxide consisting of a hydrophobic propylene oxide moiety combined with one or more hydrophilic ethylene oxide moieties. Suitable anionic emulsifiers include sulfates of higher aliphatic alcohols such as sodium lauryl sulfate;
Alkylaryl sulfonates such as the sodium salt of t-octylphenyl sulfonate, sodium dioctylsuccinate, aliphatic alkylalkanolamide disodium sulfosuccinate, and ammonium sulfate or phosphate esters of alkylphenoxy poly(ethyleneoxy)ethanol. Examples include salts (oxyethylene content is 3 to 30 mol per alkylphenol). Suitable cationic emulsifiers include N-dodecyltrimethylammonium chloride and N-vinylbenzyltrimethylammonium chloride. Generally, the copolymer emulsions of the present invention contain up to 0.5% by weight of emulsion, preferably from 0.05 to 0.4% by weight, based on the weight of the emulsion.

The vinyl acetate-ethylene copolymer emulsions of the present invention are prepared by conventional batch, semi-continuous or continuous polymerization processes. These include, for example, US Pat. No. 3,708,38
No. 8, U.S. Patent No. 3,827,996, U.S. Patent No. 4164
No. 489 and “Applications of synthetic resin emulsions J ((
The Application of 5ynthe
tic Re5 in Emulsions) by H. Walson, Ernest Penn Ltd., 1972, pp. 85-132]. The preferred polymerization method used to prepare the vinyl acetate-ethylene copolymer emulsions of the present invention involves first adding water, polyvinyl alcohol or a mixture of polyvinyl alcohols dissolved in water, a small amount of an emulsifier, and optionally a mixture of anionic and nonionic emulsifiers. An aqueous phase containing: Buffers are often added to maintain the pH of the system between 2 and 6. Buffers include compounds such as sodium acetate, sodium benzoate, sodium bicarbonate, ammonium hydroxide, disodium phosphate, and the like. The amount of buffer used is generally about 0.02% based on the total amount of emulsion.
It is 5 to 2.0% by weight. The aqueous phase is thoroughly purged with nitrogen and heated to 35-80°C, preferably 45-65°C. Vinyl acetate, often in a mixture with small amounts of other monomers, is then added, followed by a suitable amount, often o,ot-t, preferably about 0.05-0.5% reduction based on the weight of the emulsion. Add agent.

Suitable reducing agents include sodium metabisulfite, sodium formaldehyde sulfoxylate, zinc formaldehyde sulfoxylate, ahicorbic acid, and the like.

The reaction vessel is then sealed and pressurized with ethylene to reach reaction pressure. A suitable pressure range is 5 to 100 atmospheres, preferably 10 to 60 atmospheres. The amount of ethylene introduced into the copolymer is influenced by the reaction pressure, agitation and the viscosity of the polymerization medium. Therefore, increasing the ethylene content in the copolymer is achieved by increasing the pressure and/or by increasing the agitation.

Stirring is usually done in such a way that the polymerization medium is sufficiently agitated to maximize heat transfer and mixing.

Polymerization is initiated by addition of a catalyst solution. It is often advantageous to use hydrogen peroxide as catalyst, but potassium, sodium or ammonium persulfate can also be used. Organic catalysts such as cumene hydroperoxide or t-butyl hydroperoxide are often used.

After initiation of the emulsion polymerization, the remaining vinyl acetate (if not all the vinyl acetate is initially added) is gradually added to the reaction mixture emulsified in water, often along with latent and active crosslinking monomers. . Generally, this slow addition is carried out over a period of 2.5 to 5 hours.Additionally, additional catalyst solution is gradually added to allow the polymerization reaction to continue for 35 to 5 hours.
The temperature is maintained at 80°C, preferably 45-65°C. The catalyst is
It is also possible to add the redox agent initially or continuously during the polymerization. Water is often circulated within the jacket to cool the reaction vessel and remove excess heat from polymerization. The catalyst usually has a total amount of 0.025 to 2.0, preferably 0.05 to 1%, based on the weight of the emulgitane.
amount is added throughout the entire emulsion polymerization process. After the free emulsion is reduced to less than 1%, the emulsion is cooled and excess ethylene pressure is vented.

Auxiliary agents such as antifoam agents, biocides, etc. can be added to the final copolymer emulsion. The solids content of the emulsion copolymers of the present invention is between 35% and 65%, preferably 4%.
It is 5-60%. The viscosity of the copolymer emulsions of the present invention is relatively high, typically 1000-20000 cps as measured on a Brookfield viscometer at 6 RPM.
, preferably about 2000 to 12000 cps. The molecular weight of the copolymers of the invention is high. That is, the intrinsic viscosity, which is a measure of polymer molecular weight, is 0.5 to 2.5 dl/g, preferably 0.8 when measured in benzene at 30°C.
~1.5 dl/g. Intrinsic viscosity is measured by the usual method [
Principles of Polymer Chemistry, Susumu Paul Flory
Lymer Chemistry, by Paul
Flory) Cornell University Press 1953 309-31
See page 4].

In this or formulated form, the vinyl acetate-ethylene copolymer emulsions of this invention are useful as adhesives, coatings, and sizes.

Commonly used formulation materials such as fillers and pigments, plasticizers, solvents, tackifiers, biocides and antifoam agents, and polyvinyl acetate latex, styrene latex,
Other latexes such as butadiene latex or acrylic latex are often added. The materials listed below are merely illustrative and not limiting. Extending agents include clay, magnesium silicate (talc), titanium dioxide, barium sulfate, aluminum oxide, calcium carbonate, and the like. Both organic and inorganic pigments can be used. Examples of organic pigments are Red Lake C1 Resole Red, Phthalocyanine Blue,
There are Hansa Yellow and others.

Examples of inorganic pigments include carbon black, chrome green, cadmium sulfide, red iron oxide, and the like. As a plasticizer,
Examples include butylbenzyl phthalate, dibutyl phthalate, dioctyl phthalate, and epoxy plasticizers. Examples of the solvent include aromatic solvents such as toluene and xylene, and chlorinated solvents such as trichloroethylene. Tackifiers are often rosin-based.

(Example) Next, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited thereto.

In the examples, unless otherwise specified, all parts are parts by weight, and all particle sizes mean average particle sizes.

Example 1 The following was included: a variable hyperopic insulator set at 250 rpm, a temperature control system, a feed pump, means for purging the reaction vessel with nitrogen and means for pressurizing with ethylene, and heating and cooling. 5 with a jacket for
012 Stainless steel pressurized reactor: Polyvinyl alcohol A" 3609 Polyvinyl alcohol B' 3609 Polyvinyl alcohol D' 5409) IJ): / X-100
'729 water (deionized water)
160009 After heating and dissolving the polyvinyl alcohol, add 108 g disodium diphosphate vinyl acetate 90QQ9 sodium formaldehyde sulfoxylic acid 309 The container is then sealed, purged with nitrogen and 40 g
Heat the contents to 50° C. while pressurizing to atmospheric pressure. 10%
Polymerization is initiated by adding hydrogen peroxide solution 2009. Once the onset of polymerization is observed due to an increase in the temperature of the reaction vessel, the following feeds are started at 15 y/min: 4500 g of vinyl acetate at the same time;
A 5% hydrogen peroxide solution is added to maintain the polymerization reaction. Add approximately 10009. Once the free vinyl acetate monomer is reduced to less than 1%, the contents of the reaction vessel are cooled to 40°C, vented of excess ethylene, and brought to ambient pressure. The properties of the emulsion are shown in Tables 1 and 2.

Examples 2-6 and Comparative Examples Cl-C6 The amount and type of polyvinyl alcohol and Triton X-100 were adjusted according to the general formulation and method of Example 1.
Various emulsions are prepared by changing only the amount of '.

These amounts and types of polyvinyl alcohol, as well as the average degree of hydrolysis of the polyvinyl alcohol mixtures used in these examples, are shown in Table 2.

Note) (1) Triton X-100 is octylphenoxypolyethoxyethanol containing 10 moles of oxyethanol per mole of octylphenol. ROHM・
& Haas Company (Roha+ & Har
Obtained from s Company).

(2) Polyvinyl alcohol A has a 4% solution viscosity of 20
℃ and a partially hydrolyzed polyvinyl alcohol with a degree of hydrolysis of 86 mol%.

(3) Polyvinyl alcohol B has a 4% solution viscosity of 20
℃ and a partially hydrolyzed polyvinyl alcohol with a degree of hydrolysis of 88 mol%.

(4) Polyvinyl alcohol D has a 4% solution viscosity of 20
5 cps and a degree of hydrolysis of 89 mol%.

Table 1 1 50.6 16J 5800 i16
．． 1 0.96 0.62 SL, L 16
．． 4 5aQQ 4L4 1.4Q Q, 5
C150,716,3580016,51,08L,S
C251,415,9560017,50,600,4
351,016,0540036,40,900,6C
a 51.2 16.4 5300 20.5
1.40 0.44 50J lla, 2
5700 28.4 1.21 1.15 5
1.1 16J 5500 39.5 1.
12 0.7C451,016,0800016,50
,731,2C551,216,2280023,10
,701,2651,016,l 6100 3
0.6 1.30 0.8C1l 51.1 1
5.9 5900 20.6 1.41 L,
QA 56.4 5300 22.8
1.24 0.7B 55J 370
0 32.1 1.10 0.7C55,1450
038, 11, 120, 7 Note) (5) The ethylene content in the polymer is determined as follows: About 19% of the dry polymer is dissolved in a mixture of acetone, methanol and water (5:3:2N00 liquor). Melt.

A solution of 0.5N sodium hydroxide in a mixture of methanol and water (9:l) was then added to the polymer sample to initiate hydrolysis of the vinyl acetate portion of the polymer.
Perform at ℃ for 2 hours. At the end of this time, unreacted sodium hydroxide is back titrated with 0.5N hydrochloric acid. After further dry titration, the weight percent of vinyl acetate (VAC) and the weight percent of ethylene can be calculated as follows: VAc (wt%) = (Vt VυXNX8,609/In [where Vt'' polymer Acid (Frog) Vl required for sample titration - Hydrochloric acid (j112) for empty titration N = normality of hydrochloric acid solution m = weight of polymer sample PVA = polyvinyl alcohol] Next, the ethylene content is calculated as follows.

Ethylene content (%) in the polymer = 100 - VAc (wt%) - PVA (wt%) / 10
0- PVA (wt%) (6) Brookfield Viscometer (7) Polymer samples are extracted with benzene in a Soxhlet extractor. The benzene solution is then evaporated and the residue is weighed.

(8) In measuring the intrinsic viscosity, a sample θ, 59 of the benzene extract of the polymer is dissolved in benzene 100×12 and filtered. The flow time of the solution prepared in this way was measured using an Upperode viscometer [Tamson Zettermeyer].
(Netherlands) (Tamson Zoetermeier,
The flow time is compared with the flow time of benzene solvent at 30° C. using a method obtained from Hof 1and). Relative viscosity is the flow time of the solvent, which is the difference between the flow time of the solution. The intrinsic viscosity is then calculated from the relative viscosity and copolymer solids content (9/solution d12) using the Huggins equation. Using the Huggins equation to calculate the intrinsic viscosity is
Encyclopedia for Polymer Science and Technology
for P! ymer 5science andT
technology'', (Wiley, New Yo
rk, 1971), Vol. 15, p. 634.

(9) Particle size is determined by Pruckhaven Instrument Co., Ltd. (B
rookhaven Instruments Co.
) obtained from laser scattering (laser
measurement using a scat- ering device.

Table 2 B=1.0 D=1.5 2 0.2 A=1.0 888
=1.25 D=, 0.75 CI (1,2C=3.0 99C20
,75A=1.0 88B=1.25 D=0.75 3 0.2 A=1.0 888
=1.25 C=0.25 C30,2C= 1.25 94D=1.25 4 0.2 ^=2.0 87D=0
．． 5 5 0.2 ^=1.0 118B=
1.0 C=0.2 C40, 2 people=0.9 89 B=(1,3 C=0.3 C50,2^=1.0 86 6 0.2 B=1.0 88D
= 4.0 C60, 2D = 6.0 99 Note) (10) Polyvinyl alcohol C is partially hydrolyzed polyvinyl alcohol with a 4% solution viscosity of 65 cps at 20°C and a degree of hydrolysis of 99 mol%. It is.

Example 7 The vinyl acetate-ethylene copolymer emulsions of Examples 1-6 and Comparative Examples 01-C6 and three commercially available vinyl acetate-ethylene copolymer emulsions, A, B and C, were prepared as follows: Tested in adhesive formulations.

Thickening Response Test In this test, an emulsion is tested for its ability to thicken by adding a solvent to the emulsion. In the test, 200 g of polymer emulsion is placed in a 2501 plastic beaker at room temperature.

Measure the viscosity of the emulsion with a Brookfield viscometer at 6 rpg+. Next, place a stirrer in the beaker and stir the emulsion at a speed that does not trap air bubbles. While stirring, add 209 grams of toluene to the beaker and stir the mixture for an additional 5 minutes. After this time, the stirrer is removed and the viscosity of the emulsion is measured with a Brookfield viscometer at 6 rpm. The ratio of the viscosity of the emulsion-toluene mixture: the viscosity of the initial emulsion is referred to as the thickening factor j. A high thickening factor means a good thickening response, which is desirable in adhesive compositions.

Dilution Sedimentation Test This test measures the precipitation of polymer emulsion particles when the emulsion is diluted. This resembles long-term storage conditions and is therefore a test of the emulsion's storage stability. The vinyl acetate-ethylene copolymer emulsion was diluted with water to a solids content of 3%, and then the diluted emulsion 30xQ was added to an inner diameter of 14.
into a flat-bottomed glass cylinder. The height of the solution inside the tube is approximately 200u. After 72 hours, the height of the sediment layer consisting of concentrated polymer particles at the bottom of the tube is measured.

Calculate the diluted sediment (%) as follows: Diluted sediment (%) = [Thickness of bottom sediment in mm/Height of diluted solution + 111)) Good storage stability.

Peel strength test of vinyl acetate-ethylene copolymer emulsion at O,1
Using an applicator with a gap of 5+uy,
Apply to a piece of plywood measuring c shoulder x 30 cm x 3 cm.

Next, a polyvinyl chloride film with a thickness of 0.2 x m is placed on the plywood and pressed with a rubber roller. 25 laminates
℃ and 65% relative humidity for 48 hours, then
The laminate is cut into 20 pieces, each 15cx3cm. Each of these specimens was tested using an Instron tester at 25°C and 65% relative humidity.
Subject to 180° peel test at crosshead speed of Rrx 1 minute. Peel strength is the average of the six specimens tested and is given in kg/3 C3I. It is desirable that the peel strength is higher than 1. Creep rate test of vinyl acetate-ethylene copolymer emulsion of 0.1
Using an applicator with a gap of 511 m, 30
Apply to a piece of plywood with dimensions cxx30czx3cm.

A piece of polyvinyl chloride film with a thickness of 0.2 zyz,
Place it on the plywood and press it with a rubber roller. The laminate,
Dry for 48 hours at 25°C and 65% relative humidity, then cut the laminate into 20 15ci+x3cx pieces. Each specimen is tested by first heating it in an oven at 60° C. for 930 minutes. Next, a 5009 weight is suspended at a 90 degree angle to the test piece attached to the polyvinyl chloride film. After 60 minutes, measure the length of the peeled film. The creep rate is calculated as follows.

Creep rate (+U/min) = length of peeled film/
60 All measurements are shown in Table 3.

Table 3 1 9.1 0,7 5. :I
O, 5628, 80, 85, 10, 64 CI 6.4 +, 9 3.6
1.8C25,9Q,8 2,9 1.
43 8, Ill O, 75, 0G, 58
C371, 74, 51, 5 49, 10, 95, 0G, 52 5 9 G, 8 5.2 0.
55C47,92,44,81,4 C5g 3.11 4.6 1.
96 8.6 0.7 5.1
0.65G6 B, 4 0.6 3
．． 7 1.2A 6.4 +
4. go, gB 7,8
1.2 4.8 1.2C7,81,24,6
1,2 Vinyl acetate-ethylene copolymer emulsions prepared according to the present invention (e.g. Examples 1-6) were compared to Comparative Example C
When compared with l-C6 and three commercially available emulsions, A, B and C, it has excellent storage stability as determined by the dilution precipitation test and good thickening factor as determined by the thickening response test. , and the creep resistance and peel strength were also found to be excellent.

However, it will be readily understood that the laminates that can be produced using the vinyl acetate-ethylene copolymer emulsion of the present invention are not limited to plywood-polyvinyl chloride film. Can also be used to bond fabric and paper, fabric and paperboard; metal foils such as aluminum foil and wood, paper or paperboard.

A variety of other films, such as polyethylene and polypropylene films, borisdylene films, etc., can be combined with cloth, paper, paperboard, wood, and the like. The emulsions of the present invention can also be used as packaging adhesives, either alone or in combination with previously formulated materials.

The foregoing examples illustrate preferred methods of carrying out the invention;
It is shown only to illustrate the results obtained. These examples are not intended to unduly limit the invention, which is intended to include the reagents and processes described in the claims and equivalents thereof.

Patent applicant Dairen Kaji Kogyo Co., Ltd. Agent Patent attorney Aoyama Ao and one other person Procedural amendments Address: 301 Pleasant Fusuma, 301 Songjiang Road, Taipei City, Taiwan Name: Dalian Karate Industrial Co., Ltd. 4, Agent: 5 Date of amendment order: Voluntary action: 7 Contents of amendment: 1. As attached to the application form: 2: Specification, page 49: 6 In the row, "Dalian conversion rate" is corrected to "Dalian conversion rate."

that's all

Claims (1)

[Claims] 1. In producing an aqueous vinyl acetate-ethylene copolymer emulsion, the obtained emulsion exhibits excellent performance in a thickening response test and a dilution precipitation test, and contains 5 to 40% by weight.
(a) at least one emulsifier in an amount of 0 to 0.5% by weight of the total emulsion; and (b) a protective colloid in an amount of 2.0 to 5.0% by weight of the total emulsion. A method for producing an emulsion, characterized in that the copolymer is copolymerized in the presence of a copolymer (the colloid essentially consists of a copolymer of vinyl acetate and vinyl alcohol, the average vinyl acetate content of which is 11 to 14 mol%). 2. The manufacturing method according to claim 1, wherein the thickening factor is 8 or more in the thickening response test. 3. The manufacturing method according to claim 1, wherein the diluted precipitate is 1% or less in the diluted precipitate test. 4. The amount of emulsifier used is 0.
05 to 0.4%. 5. The method according to claim 1, wherein the emulsifier is octylphenoxypolyethoxyethanol having 10 to 30 oxyethylene units. 6. The method according to claim 1, wherein the protective colloid is a mixture of two or more copolymers of vinyl acetate and vinyl alcohol having an average vinyl acetate content of 11 to 14 mol%. 7. The method according to claim 1, wherein the amount of protective colloid is 2.5 to 5% based on the weight of the emulsion. 8. The method according to claim 1, wherein the ethylene content is 10 to 25% by weight of the copolymer. 9. The method of claim 1, wherein the copolymer emulsion also contains 0.5 to 5% by weight of an ethylenically unsaturated acid or salt thereof in the copolymer. 10. exhibiting excellent performance in the thickening response test and dilution precipitation test and having an ethylene content of 5 to 40% by weight, and (a) at least one emulsifier in an amount of 0 to 0.5% by weight of the total emulsion; and (b) a protective colloid in an amount of 2.0 to 5.0% by weight of the total emulsion (the protective colloid consists essentially of a copolymer of vinyl acetate and vinyl alcohol, the average vinyl acetate content being 11 to 14 mol%). An aqueous emulsion of a vinyl acetate-ethylene copolymer, characterized in that it is copolymerized in the presence of 11. The thickening factor was 8 in the thickening response test.
Vinyl acetate according to claim 10, which is
Ethylene copolymer/aqueous emulsion. 12. The aqueous vinyl acetate-ethylene copolymer emulsion according to claim 10, wherein the diluted precipitate is 1% or less in the diluted precipitate test. 13. The amount of emulsifier used is 0 based on the emulsion weight.
．． 11. The vinyl acetate-ethylene copolymer aqueous emulsion according to claim 10, wherein the vinyl acetate-ethylene copolymer aqueous emulsion has a content of 0.05 to 0.4%. 14. The vinyl acetate-ethylene copolymer aqueous emulsion according to claim 10, wherein the emulsifier is octylphenoxypolyethoxyethanol having 10 to 30 oxyethylene units. 15. The vinyl acetate-ethylene copolymer according to claim 10, wherein the protective colloid is a mixture of two or more copolymers of vinyl acetate and vinyl alcohol having an average vinyl acetate content of 11 to 14 mol%.・
Aqueous emulsion. 16. The vinyl acetate-ethylene copolymer aqueous emulsion according to claim 10, wherein the amount of protective colloid is 2.5 to 5% based on the weight of the emulsion. 17. Vinyl acetate according to claim 10, wherein the ethylene content is 10 to 25% by weight of the copolymer.
Ethylene copolymer/aqueous emulsion. 18. The aqueous vinyl acetate-ethylene copolymer emulsion according to claim 10, wherein the copolymer emulsion also contains 0.5 to 5% by weight of an ethylenically unsaturated acid or salt thereof in the copolymer. 19, exhibiting excellent performance in thickening response tests and dilution precipitation tests, having an ethylene content of 5 to 40% by weight, and containing (a) at least one emulsifier in an amount of 0 to 0.5% by weight of the total emulsion; (b) Protective colloid in an amount of 2.0 to 5.0% by weight based on the total amount of the emulsion (the protective colloid consists essentially of a copolymer of vinyl acetate and vinyl alcohol, and the average vinyl acetate content is 11 to 14 mol%) A laminate, characterized in that it consists of a support and a continuous coated surface, which are adhered to each other by an aqueous emulsion of a vinyl acetate-ethylene copolymer copolymerized in the presence of .).