JPS6399212A - Production of polymer dispersion - Google Patents

Abstract

(57) [Abstract] 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 relates to a method for preparing polymer dispersions, such as fibers.

The present invention relates to a method for making solvent-based polymer dispersions suitable for forming film, coating or molding compositions.

[Conventional technology]

Many fibers, films, and coatings are made from polymer solutions. However, the disadvantage is that certain monomers that impart the desired properties to the polymers produced may result in polymers that are poorly soluble in common solvents. For example, polymers containing a high percentage of vinylidene chloride may Although it is suitable for the formation of flame retardant fibers and films as well as gas barrier coatings, it has low solubility in most solvents. The present invention creates polymer dispersions containing polymers that are insoluble in the dispersed phase but have particle sizes that are small enough to allow the formation of fibers and films from the dispersion.

US Pat. No. 4,202,924 describes a polymer dispersion comprising an acrylic solution polymer in which is dispersed an acrylic polymer prepared by emulsion or suspension polymerization.

The method for producing a polymer dispersion according to the present invention comprises placing polymer particles in a solvent containing one or more core particles of a first polymer that is insoluble in a solvent and encapsulated inside a second polymer that is soluble in a solvent. It is characterized by being dispersed.

The polymer particles are prepared by polymerizing the monomers forming the second polymer in the presence of an emulsion of the first polymer. Preferably, the first polymer is prepared by emulsion polymerization. The monomer for the second polymer needs to be added without additional surfactant so that polymerization occurs around the first polymer particles.

The polymer particles may be core/molds in which a shell of the second polymer surrounds a single core of the first particle, the second polymer being emulsion polymerized and the particles undergoing the entire process of polymerization. If the particles remain in the emulsion form, they will generally be of this type. In particular, when most or all of the monomers forming the second polymer are soluble in the polymerization medium, large polymer particles may precipitate during the polymerization process, especially if the second polymer is not. to form a second polymer. These particles include one or more particles (
(usually one or more) core polymer particles.

The composition of the first polymer determines the desired properties of the fiber, film or coating made from this polymer dispersion, such as flame retardancy, impact resistance, or oxygen.

According to one of the preferred embodiments of the present invention, the carbon dioxide is appropriately selected to provide low permeability to carbon dioxide or water vapor, etc.
At least the first polymer? (lffi%, preferably at least 85% by weight) of vinylidene chloride to impart flame retardancy. According to another example, the first polymer is an alkyl group having from 3 to 6 carbon atoms in the alkyl group. It contains at least 70% by weight of acrylate, thereby forming rubbery core particles for impact-resistant films, coatings or molding compositions.The first polymer may be crosslinked, for example ethylene glycol. It may contain from 0.2 to 10 double percent of units of crosslinking monomers having two or more sides of unsaturation, such as diacrylate or dimethyl acrylate or 1,4-butane dimethyl acrylate.

The first polymer is formed by conventional emulsion polymerization using an emulsion promoting surfactant and a free radical initiator. The surfactant used in preparing the core polymer is preferably an anionic surfactant such as sulfates, sulfonates, phosphates, phosphonium salts of ethoxylated alkylphenols. Alternatively, it may be a nonionic active agent containing one or more polyalkylene oxide chains. 'tl used, ii
The n-group initiator is preferably a persalt such as potassium peroxydisulfate or ammonium peroxydisulfate that is soluble in the aqueous phase. All or part of the polymer used to make the core polymer can be added continuously during the polymerization operation, as can the initiator. Chain transfer agents such as tertiary alkyl mercaptans may be used during the polymerization process to control molecular weight. The particle size formed is usually less than 1 micron, preferably less than 0.5 micron, for example 50 to 200 nanometers (nm).

According to another example, the first polymer may be a siloxane polymer, such as a silicone elastomer. The functional polyorganosiloxane-based silicone elastomer of cross-linked vinyl is
It is available in cars as a latex with a particle size of 00 nm or less.

The core polymer includes particles of the first polymer described above and particles of a block copolymer having at least one segment compatible with the first polymer and at least one segment compatible with the second polymer. This block copolymer may be, for example, a block copolymer consisting of a main monomer component of the first polymer and a main monomer component of the second polymer. This block copolymer is preferably used in an amount of 10% or less, for example 1 to 5%, of the weight of the total core particles. The block copolymer emulsion can be added to the first polymer emulsion prior to polymerization of the monomers forming the second polymer. The incorporation of block copolymers increases the stability of the dispersions made according to the invention, particularly the resistance to shear encountered during fiber formation.

Once the emulsion of the first polymer is obtained, monomers for the second polymer are added to initiate polymerization. The monomers for the second polymer may be added all at the beginning of the second polymerization, or may be added continuously in portions throughout the entire polymerization process.

In the latter case, the proportion of monomers added during the polymerization is
It depends on the amount of heptamer present at the beginning of the polymerization. Monomers for the second polymer are selected from a wide range of unpolymerized, unsaturated monomers. For example, acrylic esters such as ethyl acrylate, butyl acrylate, methyl acrylate, propyl acrylate, hexyl acrylate, 2-ethylhexyl acrylate, hydroxyethyl acrylate, the corresponding methacrylates, styrene, acrylonitrile, methacrylonitrile, vinyl chloride, vinylidene chloride, vinyl Examples include acetate.

In this case, the second polymer is a copolymer containing a certain proportion of the main monomer of the first polymer. For example, if the first polymer is a vinylidene chloride polymer, the second polymer may be a copolymer of vinylidene chloride and a comonomer such as acrylonitrile or styrene. The proportion of vinylidene chloride in the second polymer is
The polymer is selected to be soluble in the solvent used to make the polymer dispersion. In this case, it is preferable to increase the proportion of vinylidene chloride in the solvent to a level close to the maximum amount obtainable. This results in a dispersion containing a higher vinylidene chloride content in the total polymer than any vinylidene chloride copolymer obtained dissolved in the solvent. Such dispersions can form films and coatings in which properties such as flame retardancy and gas barrier properties are maximized due to the high vinylidene chloride content.

A polymerization initiator for the second polymer is added together with the monomer. In this case, the free radicals are entrapped within the core particles and polymerization occurs to the extent that it occurs as soon as the monomer for the second polymer is added without the addition of an initiator. In this case it is desirable to subsequently add an initiator. Second
If a portion of the monomer for the polymer is added continuously during the polymerization, the addition of the initiator may be followed after the addition of the monomer, thereby ensuring a high conversion of monomer to polymer. be done. The amount of initiator used is
0.05 to 1.0% based on the monomer for the second polymer.
0% by weight is preferred. For example, the initiator is an azo compound such as azobisisobutylnitrile.

Redox partners such as peroxides, persalts, or hydroperoxides, or bisulfates, including metabisulfites or dithionites. Catalysts of this initiator, such as steel ion pairs such as copper sulfate and iron(1) ammonium sulfate used as catalysts for redox initiators, are used to enable polymerization at low temperatures. The polymerization temperature is approximately 25-100°C.

The second polymer is uncrosslinked or slightly crosslinked. For example, the second polymer contains 0.2 to 5% crosslinked heptamer.

When both the first and second polymers are tightly crosslinked, the polymer particles themselves form an interdigitated polymer network that is insoluble in most solvents. If the first polymer is cross-linked while the second polymer is slightly cross-linked, the polymer particles will have some entanglement between the polymer chains of the second polymer and the polymer network of the first polymer. This results in a half-phase five-member polymer network. When such a semi-phase five-member polymer network is dispersed in a solvent for the second polymer, most of the second
The polymer dissolves during dressmaking, but some remains as a solvated shell around the particles of the first polymer. This increases the stability of the polymer dispersion in subsequent steps.

The seven-mer composition used to make the polymer shell is added into a preformed emulsion of the core polymer or added late in the core polymer polymerization process. In the latter method, the addition of monomers for the second polymer comprises at least 85% by weight of the monomers forming the core polymer.
, for example, when about 95% by weight has been polymerized. Preferably, the initiator is added at the same time as or prior to the addition of the monomer for the second polymer. shot growth polymerization
on), graft polymerization of some second stage monomers onto the core polymer takes place. This results in a dispersion having a suspended shell of second stage polymer around the core polymer. Shot growth polymerization allows core/
Allowing the formation of a shell polymer.

Preferably, the polymer particles are isolated from the polymerization medium before being dispersed in the solvent for the second polymer. The polymer is removed from the emulsion by freezing and thawing techniques or by coagulation with an electrolyte such as sodium chloride or potassium sulfate. In another example, an emulsion of a core/forge polymer is dispersed in a solvent for a second polymer and the continuous phase of the emulsion (typically water) is removed, which is not preferred. . Examples of solvents include acetone and dimethylformamide, which are useful in fiber and film formation and do not dissolve polymers with high vinylidene chloride content; hydrocarbons such as white spirits and xylene, and methyl isobutyl, which are widely used in coating compositions. Ketones such as The dispersed particles generally have a size of less than 1 micron, for example from 80 nm to 1 micron, depending on the degree of swelling of the core polymer and the associated semi-phase five-member polymer network by the solvent.

An example of the second polymer is a fiber-forming acrylonitrile polymer. The polymer contains at least 50% by weight acrylonitrile, preferably at least 85%. This second polymer may be composed of, for example, 86-95% by weight of acrylonitrile, 4-12% by weight of methyl acrylate, and up to 3% by weight of monomers containing carboxylic or sulfonic acid groups to impart dyeability. It is a copolymer. The first polymer used with this fiber-forming acrylonitrile polymer may include vinylidene chloride to improve flame retardancy, butadiene-acrylonitrile copolymer or cross-linked butyl acrylate to increase fiber flexibility. - Elastomers such as topolymers or siloxane polymers to improve soil resistance.

The ratio of the first polymer forming the core particles to the fiber-forming acrylonitrile polymer is, for example, 1 by weight.
0890-50:50, preferably 10:90-30
For example, polymer particles containing 20 to 30% by weight of core particles of vinylidene chloride polymer are dispersed in a solvent for acrylonitrile polymer to form a dispersion having good spinnability and high flame retardancy. Form.

When this fiber-forming acrylonitrile polymer is used as a second polymer, it can be used as a slurry of polymer particles, e.g., having a particle size of 10 to 100 μm and containing a plurality of core particles, each encapsulated in a matrix of acrylonitrile polymer. Precipitate.

The present invention includes a fiber-forming acrylonitrile polymer composition that is a dispersion comprising first polymer particles dispersed in a solution of a fiber-forming acrylonitrile polymer dissolved in a solvent, wherein the particles of the first polymer are It is insoluble in the solvent. Examples of suitable solvents include dimethylformamide, dimethyl sulfoxide, dimethyl acetamide, concentrated nitric acid, and 40-60% by weight of sodium thiocyanate or zinc chloride, preferably about 50% by weight, which allow dry spinning of fibers. There is an aqueous solution. A dispersion in an aqueous sodium thiocyanate solution is a dilute solution of sodium thiocyanate, for example 8-203!, as is well known in the production of acrylic fibers. f
Wet spinning in a solution containing fi% sodium thiocyanate is possible. Dispersions in dimethylsulfoxide, dimethylacetamide or nitric acid can be wet spun into aqueous solutions of solvents. Dispersions of zinc chloride in aqueous solutions can be further wet spun into dilute zinc chloride solutions.

In another embodiment of the invention, the first polymer is a silicone elastomer and the second polymer is a fiber-forming acrylic polymer, preferably an alkyl acrylate and/or methacrylate polymer. Ab+ dispersions formed with these polymers are useful as antifouling paints. Silicone elastomers are known to be useful in preventing marine organisms such as algae and shells from adhering to underwater surfaces. However, these materials are not widely used, especially for ship hulls, because they are easily damaged. The acrylic polymer used as the second polymer with such silicone elastomers is a combination of methyl methacrylate and an alkyl acrylate containing 3 to 6 carbon atoms in the alkyl group, such as butyl acrylate.
A copolymer having a weight ratio of :so to 80 :20 is preferred. This copolymer forms a tough film. When silicone elastomer particles encapsulated in acrylate and/or methacrylate esters in a polymer are dispersed in a solvent such as methyl isobutyl ketone, the acrylate polymer dissolves in the solvent while the silicone elastomer does not. When the dispersion is formed into a film or coated onto a surface, the acrylate polymer initially forms a continuous phase, but phase separation of the polymer occurs. The low-energy silicone polymer migrates towards the free surface of the film, and the formed film or coating gains mechanical strength from the acrylate polymer, but has a low-energy surface made of silicone that prevents marine organisms from adhering to it. do. Silicon elastomer is
Preference is given to based on crosslinked vinyl-functional polyorganosiloxanes with residual vinyl functionality.

This grafts some of the acrylate or methacrylate monomer onto the polysiloxane and helps maintain the polysiloxane on the surface of the film.

In another embodiment of the invention useful for making molded articles, the solvent in which the polymer particles are dispersed is a polymerizable heptamer. Preferred salts are methacrylates and acrylates such as methyl acrylate, butyl acrylate, ethyl acrylate, and styrene. The dispersion formed includes core particles of a first polymer dispersed in a solution of a second polymer in a polymerizable monomer. The composition can be molded, for example, by injection, extrusion, or compression molding, and the monomer acting as a solvent can be polymerized by heating. The molded article includes core particles of a first polymer dispersed in a blended matrix of a second polymer and a polymer of monomers that acted as a solvent.

This molding composition is particularly suitable for producing denture plates.

Traditional materials for forming acrylic dentures are molding compositions that generally consist of powders of acrylic polymers, such as methyl methacrylate polymers, and methyl methacrylate monomers. This methyl methacrylate monomer is
Polymerization occurs when the composition is molded. A drawback of the manufactured denture plate is the low impact strength of the methyl methacrylate polymer used. Dentures formed from this are not only easily broken when dropped, but also tend to break when chewing hard food. In order to improve the impact strength of denture plates, e.g.
427274, it has been proposed to incorporate rubbery materials based on butadiene or by means of microdispersions of rubbery phases. However, it has been found that these improved denture-forming compositions are difficult to form into uniform denture plates.

A molding composition according to one embodiment of the invention used for the manufacture of a denture plate comprises a mixture of a polymer powder and a methyl methacrylate monomer, the polymer powder containing 3 to 6 carbons in the alkyl group. The composite particles are made of composite particles having a hard acrylic polymer shell of at least 60 weight polymerized methyl methacrylate surrounding a core comprising a rubbery polymer that is a crosslinked polymer of alkyl acrylate with atoms.

The rubbery acrylic polymer forming the core of the composite polymer particles contains at least 70% by weight of a C3-C6 alkyl acrylate and a diurethane such as ethylene glycol diacrylate, dimethacrylate or 1,4-butane-diol dimethacrylate. Preferably, it consists of 0.5 to 10 ft 1% of units of cross-linked monomers having three or more groups of unsaturation. Most preferably, the rubbery acrylic polymer consists of 92-98% butyl acrylate and 2-8% crosslinked monomer.

The monomer composition used to make the shell is between 60 and 90
It contains 10% by weight of methacrylate and 10-40% by weight of other acrylic monomers such as acrylic acrylate and methacrylate. The monomer composition more preferably contains from 70 to 85% by weight of methyl methacrylate and from 15 to 30% by weight of an alkyl acrylate having 3 to 6 carbon atoms in the alkyl group, such as butyl acrylate. The monomer composition desirably contains a small amount, e.g. 0.2 to 5% by weight, of a crosslinking monomer such as diacrylate or dimethacrylate, when this crosslinking monomer is used in the core polymer as well as in the acid polymer. Some of the polymer particles may also be in the form of interwoven latex networks. However, the degree of cross-linking must be low enough that most of the acid polymer dissolves in the methyl methacrylate monomer; some of the hard acrylic polymers do not dissolve when the polymer powder is dispersed in methyl methacrylate. It remains as a suspended shell around the core particle and reliably improves impact resistance. The monomer forming the acid polymer preferably forms a polymer having a glass transition point Tg in the range of 50 to 100°C, preferably 60 to 85°C.

The ratio of core polymer to acid polymer is 10:90~
The range of 50:50 is preferable, and the range of 20:80 to 40:
A range of 60 is most preferred. The hardness of the core/shell polymer particles formed is preferably from 60 to 85 Shore hardness, most preferably from 70 to 80 Shore hardness when they are molded separately. The size of the core/shell polymer particles is 0.1~
A range of 0.5 μm is desirable.

The glass transition temperature Tg of the core/shell polymer is 50-100°C, preferably 6°C, as measured by differential scanning calorimetry on a small sample of the finely powdered polymer.
Preferably, the temperature is in the range of 0 to 85°C.

Core/shell polymer particles are formed by a three-step polymerization process. In this case, the Sarel polymer emulsion formed in the first two steps should involve a core polymer, i.e. this polymer should contain a rubbery acrylic polymer which is a cross-linked polymer of 0--C alkyl acrylate. On the other hand, the acid polymer formed in the third stage must be a hard acrylic polymer containing at least 60 wt polymerized methyl methacrylate. The polymer particles contain 50-85% by weight of methyl methacrylate and 15% by weight of methyl methacrylate.
an inner core of cross-linked methyl methacrylate/butyl acrylate polymer comprising ~50% butyl acrylate and a second N forming the outside of the core comprising cross-linked poly(butyl acrylate). . The second stage of polymerization is preferably carried out without a surfactant so that the core polymer becomes a latex semi-intruded polymer network. The weight ratio of the core polymer of the inner layer to the crosslinked butyl acrylate layer forming the outer layer of the core is preferably in the range of 15:85 to 60:40. Preferably, the acid polymer is a methyl methacrylate copolymer formed as described above. The overall weight ratio of core polymer to acid polymer is 20:8 (
50:50 is preferred.

The molding composition of this example is made by mixing core/shell polymer powder and methyl methacrylate monomer to form a moldable gel. The mixing ratio of polymer powder to monomer is preferably in the range of 1:2 to 4:1 by weight. For example, Ivoclar Cap
- carried out by a vibrator type mechanical mixing device. The preferred weight ratio of polymer powder to monomer is from 1:1 to 3:1 or from 1:2 to 1 depending on the molding technique utilized.
: The range is 1. Generally, the molding composition comprises a free-standing initiator for the polymerization of methyl methacrylate monomer;
Examples include organic peroxides such as benzoyl peroxide and lauroyl peroxide. The amount of initiator is preferably 0.2 to 2% by weight based on the amount of monomer in the composition, for example 0.5%.

The production of acrylic dentures by the wax mold method in denture flasks is well known to dentists and technicians.

The shape of the oral cavity is first recreated in dental stone molding material, and the artificial teeth are set in wax to create a replica of the denture. After trial fitting the wax denture into the patient's mouth, the wax denture is sealed with wax against a stone model with a base set in plaster with the teeth protruding from one half of the denture flask. Ru. When the plaster hardens, the surface is coated with a separating agent. The other half of the denture flask is further filled with plaster and assembled with the first part containing the wax denture replica for molding. The finished denture flask is then briefly immersed in boiling water, the two parts are separated, and the wax is destroyed with boiling water and a cleaning agent.

All surfaces away from the teeth are coated with a sealer before the acrylic is molded.

Molding has traditionally been done by compression molding. Compression molding has the disadvantage that, especially as the methyl methacrylate is polymerized, the composition shrinks, resulting in a denture that does not conform exactly to the mold and does not fit well in the oral cavity.

Despite this drawback, compression molding is widely adopted due to its simplicity.

Pressure injection molding methods for the manufacture of acrylic dentures are disclosed in US Pat. No. 2,806,253, British Patent No. 1,442,041 and British Patent Application No. 2,159,457. These processes make it possible to produce more precise denture moldings. These generally include means for injecting more molding composition to compensate for shrinkage during polymerization.

The present invention provides that the molding composition according to the embodiment of the present invention described above is further molded during molding and polymerization.3. and heating the methyl methacrylate to polymerize and mold the composition to form a shaped polymeric product, at least a portion of the heating being conducted at a temperature above the glass transition temperature of the polymeric product. I'm here.

The molding composition of the invention can be used to make denture plates by compression molding, but is particularly suitable for making denture plates by injection molding. UK Patent Application No. 21594
It is particularly suitable for injection molding using the apparatus described in No. 57. In this device, a plaster mold obtained by a wax mold method is placed in a chamber formed between a pair of plates separated by an elastic body. The neck of this elastomer carries an injection cylinder whose nozzle extends into the interior of the mold vessel to continue injecting the polymerizable molding composition into the mold as the composition contracts during polymerization. It is configured as follows.

According to the process disclosed in British Patent Application No. 2,159,457, the molding composition is injected into the molding space and the temperature is of the order of magnitude sufficient to effect a controlled polymerization with material flow, e.g. Raised to 70°C. A volume reduction of the material occurs as the polymerization process progresses, and this is compensated for by additional injection of molding composition. For example 1.5~
When this is substantially complete after 2.5 hours, the temperature is increased to, for example, 90-120°C to complete the polymerization.

When molding and polymerizing the compositions of the present invention, a two-step polymerization process of the molding composition can be used, but it is not necessary that the molding be carried out at temperatures above 7 g of the denture plate polymer being formed. Because the methyl methacrylate monomer in the molding composition polymerizes to create a hard polymer, this denture plate polymer has a higher Tg than the core/shell polymer powder. This denture plate polymer absorbs energy over a wide temperature range above about 70°C, similar to the properties of impact-resistant polymers, and absorbs energy from 75 to 105°C.
, preferably has a Tg in the range of 85-100°C. Molding is carried out at 90-130°C, preferably 105-120°C. Heating is carried out for 0.5 to 3 hours, preferably 1 to 2 hours.

The molded denture plate is cooled in the mold to a temperature below 7 g, for example by forced draft cooling with a fan.

The polymerized molding composition of the present invention is disclosed in British Patent No. 144
The method and apparatus described in 2041 can also be used, in which the polymerized composition is injected into the molding space and allowed to polymerize at a rate that decreases toward the injection hole. Additional polymeric composition is injected into the molding space during polymerization to compensate for shrinkage. Gradient polymerization rates are achieved by creating a temperature gradient, for example by isolating the surface of the mold in the vicinity of the injection hole as well as the reservoir of polymeric composition from the heat source. The ratio of polymer powder to methyl methacrylate in the molding composition is at the lower end of the preferred range when using this method, for example in the range from 1:2 to 1:1 by weight.

The molded denture has a Shore hardness D of 75-80, preferably 75-80. According to the present invention, the molded denture has a) lounsf 1eld notch resistance 11 impact resistance measurement of 0.07 to 0.15 or higher, and has a Tg and hardness within the preferred range. You can make it like this. It is based on a polymerizable molding composition made with a methyl methacrylate polymer and a methyl methacrylate monomer.
This value exceeds the measured notch impact resistance of sfield.

〔Example〕

The invention will be explained in more detail by the following examples. Here, "parts" and "χ" refer to weight.

Example 1 (i) Preparation of the first polymer 12 g of E, a nonionic polyethoxylate emulsifier
thylan BGH86™ and 4 g of sodium methallyl sulfonate (SMS) were dissolved in 700 g of deoxygenated water. 2-l copper sulfate solution (25g
/l and 0.8 ml ammonium iron(1) sulfate solution (39.2 g/β) was added as a catalyst for the initiator dox couple. The resulting mixture is stirred in a 31 reactor vessel equipped with a paddle stirrer, cold trap, nitrogen inlet, initiator, and monomer feed.

120 g vinylidene chloride (VDC), 16 g
of acrylonitrile (AN), and 7.5 g of ethylene glycol dimethacrylate (EGDM) were added into the vessel and the mixture was stirred for 1 hour under nitrogen atmosphere.

The pH of this mixture was adjusted to 3.65 using diluted sulfuric acid.
adjusted to.

2 ml each of ammonium persulfate (AP) (12,5 g/250 mJ) and sodium metabis sulfate (SM) (5,4 g/
250 ml) solution was added as initiator, and each initiator was fed at a rate of 3 ml per 10 minutes.

After 10 minutes, the reaction started and the supply of nanatsuma was started (60 g of VDC, 8 g of AN, 3.7 g of EG in total).
DM), monomer is 10mj! /10 minutes over 80 minutes, and the initiator was fed over 110 minutes. The latex was stirred for an additional 30 minutes. The particle size of the latex was 136 nm.

(ii) What is the second stage of manufacturing the second polymer? -(119g(7)VDC, 178g
of AN, 27 g of 5M5) was added to the above latex along with 100 g of water. The resulting mixture was further mixed with 60
Stirred for a minute, during which time a large exothermic reaction was observed.

2m each! ! A solution of AP and SM (at the same concentrations as above) was started to be added as an initiator. As soon as the reaction started, the monomer feed (total amount of VDCI 82 g, A
N162g) has started. These monomers were fed at a rate of 15 ml/10 min over 230 minutes, and the initiator was fed at 3 ml/10 min over 330 minutes. ! /10 minutes. In addition to this, 180mj? of water was added at a rate of 10 m/min in 10 minutes. It was observed that the reaction mixture became a slurry 100 minutes after adding the monomer. The slurry was stirred for an additional 30 minutes after initiator addition was discontinued. and 11m1 Nerv.
The reaction was terminated by the addition of ar+aid(TM) solution (2.5 g/25 l).

The slurry was filtered through a 10 μm mesh cloth;
It was dried in an oven at a temperature of 50°C.

No latex was recovered from the filtrate.

(iii) Preparation of the dispersion A sample of dried polymer particles having a polymerized VDC content of 54% by weight was dispersed in acetone as well as 25% by weight dimethylformamide. Each solvent dissolved the acid polymer but left the core polymer finely dispersed throughout the solution. The average size of the dispersed particles in acetone was 0.4 μm. The dispersion could be cast to form a hard, colorless, slightly opaque film, whereas a regular VDC/AN copolymer containing 54% by weight of VDC units was insoluble in acetone.

These films have a limited oxygen index (L
VDC/
Exhibits improved flame retardancy compared to films formed from solutions of AN copolymers.

Example 2 (i) Preparation of the first polymer 29.1 g of anionic emulsifier was dissolved in 650 g of deoxygenated water and 50 g of isopropanol. 4,
1 mf copper sulfate solution (25 g/E) and 0.8 ml ammonium iron(1) sulfate solution (39.2 g/E) were added. Stirred in a tank.

Then 90.2 g of VDC, 2.0 g of AN.

3.84 g of EGDM was added into the tank and the mixture was stirred for 10 minutes under nitrogen atmosphere. The pH of the mixture was adjusted to 3.65 using diluted sulfuric acid.

4ml AP each (6,25g/250mA)
and SM (>2.7 g/ml) were added as initiators, and each initiator solution was started feeding at a rate of 3.12 m!!/10 min. Immediately after the reaction started, monomer feeding started. was started (360.8 g VDC.

8.0 g AN, 15.36 g EGDM). Monomer was fed at a rate of 26.7 ml/10 min over 2 hours, while initiator was fed over 2.5 hours. The latex was stirred for an additional 30 minutes. Particle size was 78 nm.

(ii) Second step of manufacturing second polymer? - (88.0 g VDC, 64 g styrene, 6.0 g AN) was added to the latex. The mixture was stirred for 30 minutes.

4 ml of each AN used in the first stage as described above
and SM initiator solution was added. Initiator feeds were started at a rate of 8.89 ml/10 min each. Immediately after the reaction started, monomer feed (88,0 g (7) VD
C, 64.0 g (D styrene, 6.0 g AN) was started. 10.7 ml of monomer over 2.5 hours
/10 minutes, and the initiator was fed over a 3 hour period. The Latte Nox was stirred for an additional 15 minutes and the Ne
The polymerization reaction was terminated by the addition of rvanaid solution.

The latex consisting of core/shell polymer particles was filtered through a 10 μm mesh cloth. The solid polymer was recovered by adding the same amount of sodium chloride solution (1.5M) to the latex.

The resulting slurry was filtered and the polymer was washed with water. The polymer was dried in a vacuum oven at a temperature of 45-50°C.

(ii) Preparation of the dispersion 25% by weight of polymer dissolves the copolymer of styrene and VDC shell but not the polyvinylidene chloride core which is finely dispersed throughout the solution. volume ratio) dispersed in the solution. The average size of the dispersed particles was 9Qnm. This dispersion formed smooth coatings on many substrates. The total amount of VDC in the dispersion was 80% by weight, and the copolymer of VDC and styrene had a VDC content of 6%.
If it is 5% by weight or more, it is insoluble in the xylin/ketone solvent.

Example 3 (i) Preparation of the first polymer 24.6 g of anionic emulsifier were dissolved in 850 g of deoxygenated water. 6.5 mj! of copper sulfate solution (25 g/J) and 1.311 ammonium iron(1) sulfate solution (39.2 g/J) were added.The resulting solution was poured into 31 reaction vessels as in Example 1. It was stirred inside.

240 g of butyl acrylate and 9.6 g of EDGM were added to the vessel and the mixture was stirred for 10 minutes under nitrogen atmosphere. The pH of the mixture was adjusted to 3 using diluted sulfuric acid.
．． It was adjusted to 65.

Initiator solutions of 4 ml each of AP (6,25 g/250 cd) and SM (2,7 g/250 cj) were added and each was started feeding at a rate of 4 mA/10 min. supply (240g
of butyl acrylate, 9.6 g of EGDM) was started. Monomer was added at 22.9 ml/10 over 2 hours.
The initiator was fed over a 2.5 hour period.

The latex was stirred for an additional 30 minutes. Particle size is 6
It was 9 nm.

(ii) Preparation of the second polymer A second stage monomer (160 g of methyl methacrylate) was added to the above latex. The mixture was stirred for 30 minutes.

0 then 4 mj to which 4 m 12 initiator solutions of AP and SM were added respectively! Initiator feed was started at a rate of /10 minutes. Immediately after the reaction starts, the monomer supply (1
60 g of methyl methacrylate) was started. The monomer was fed at a rate of 9.4 ml/10 min over 3 hours and the initiator was fed over 3.5 hours.The latex was then stirred for 15 minutes and then
naid solution was added. The latex consisting of core/shell polymer particles was filtered through a 10 μm mesh cloth.

Add the same volume of sodium chloride solution to the latex (1,
Solid polymer was recovered by adding 5M). The resulting slurry was filtered and the polymer was washed with water. This polymer was heated at 45-50℃ in a vacuum oven.
dried in

(iii) Preparation of dispersion The polymethylene methacrylate shell is dissolved, but the polybutyl acrylate-I which contains fine molecules L&L throughout the solution
・The core is 25 times heavy in methyl ethyl ketone, which does not dissolve. 7. +
% of polymer dispersed. The average size of dispersed particles is 1
．． It was 0 μm. This dispersion formed a smooth impact resistant surface coating on many substrates.

Example 4 (i) Preparation of the second polymer In this example, the core latex used was a commercially available latex with a high VDC monomer content (greater than 90%). This latex had a particle size of 78 nm and a solids content of 50% by weight.

160 g of latex was mixed with 1420 g of deoxygenated water and 1.0 g of ammonium sulfate was added to 100 g of water. 2ml copper sulfate solution (25g/
l and 0.8 ml l of iron(1) ammonium solution (
39.2 g/f) was added.

The obtained mixture was the same as in Example 1. was stirred in a reaction tank.

106 g of AN and 10.5 g of MA were added and the mixture was stirred for 1 h under nitrogen atmosphere.

5 each. Q ml AP (6,7g/25
0m! An initiator solution of R and SM (2,7 g/250 mff) was added, each containing 3 ml/10 mff of initiator.
It began to be supplied at a rate of 1. After 5 minutes the reaction took place and the monomers (106 g AN, 10.5 g MA) were added to 10 m
//Feed was started over 120 minutes at a rate of 10 minutes. Initiator was fed over 150 minutes. A slurry of polymer particles was obtained, each particle having a core latex within a matrix of AN/MA copolymer. Ammonium sulfate was added to the latex to stabilize the slurry, which formed large polymer particles. The resulting slurry was stirred for 120 minutes. The slurry was filtered through a cloth with a 10 μm mesh.

No latex remained in the filtrate.

<ii) Preparation of the dispersion A sample of polymer particles was dispersed in a 52% by weight aqueous sodium thiocyanate solution and dimethylformamide at a ratio of 13% by weight. Both solvents dissolved the matrix polymer but not the core polymer, which was finely dispersed in the solution. The particle size of the core polymer dispersed in the sodium thiocyanate solution was 158 nm.

The total VDC content of the polymer in the dispersion was 25% by weight.
Met. VDC/ containing 10% by weight or more of VDC
The A N copolymer is insoluble in sodium thiocyanate solution.

The dispersion in dimethylformamide was cast to form a white film. These films showed significant improvement in flame retardancy compared to the AN/MA shell polymer as measured by the LIO method of the cast films. Films formed from dispersions made according to the invention showed a value of 21.3 in the LOI test versus 18.4 for the AN/MA polymer. A dispersion of sodium thiocyanate solution (aqueous solution of sodium thiocyanate diluted to 12% by weight) was wet-spun overnight to obtain a solution of 0.4% by weight.
Textile fibers were obtained. The fiber formed is 16.9
It had a strength of CN/t ex as well as an LOI value of 23.9, whereas the fiber obtained from the AN/MA shell polymer had an LOI value of 20.7.

Example 5 In this example, the latex used was a commercially available latex of butadiene-acrylonitrile copolymer (acrylonitrile content 32% by weight). 40g
of latex was mixed with 1500 g of deoxygenated water. The resulting mixture was prepared using a 3I! equipped with a stirrer, cold trap, and nitrogen inlet. was stirred in a reaction tank. 21
2 g of AN and 21 g of MA were added and the mixture was stirred for 1 hour under nitrogen atmosphere. During this time, the pH of the mixture was adjusted to 7.5 and the temperature was increased to 80°C. 1.5g of potassium bersulfate was added. The reaction started after 10 minutes and the mixture became a slurry after 30 minutes.

The mixture was allowed to stand for a total of 360 minutes to allow the reaction to proceed.

Thereafter, it was cooled and filtered through a 10 μm mesh cloth. No latex remained in the filtrate.

A sample of the polymer was dispersed at 12% by weight in a 52% by weight aqueous solution of sodium thiocyanate. This solvent dissolved the acid polymer, but left the core finely dispersed throughout the solution. The total core content was 5% based on the total polymer weight.

This dispersion was able to spin fibers rich in flexibility.

In the examples, the core latex used is a silicone elastomeric latex based on a cross-linked vinyl-functional polydiorganosiloxane;
It had a particle size of approximately 1100n.

30 parts by weight (based on solid polymer) of the latex were diluted with water containing 0.5 parts by weight of potassium bersulfate to a solids content of 12% and heated to 80°C. A monomer blend of 49 parts by weight of methyl methacrylate and 21 parts by weight of butyl acrylate was added over 1 hour and maintained at a temperature of 80°C. A latex of core/shell polymer particles with a refund particle size of 137 nm was formed.

The polymer was isolated from the latex by the freeze-thaw method. A sample of the polymer was dissolved in methyl isobutyl ketone and cast to form a tough film with a low energy surface of silicone elastomer.

Example 7 Stage 1: Preparation of polybutyl acrylate core The reaction was carried out in 21 reaction flasks equipped with a cold trap, nitrogen inlet, thermocouple, paddle type stirrer, and monomer feed.

Perlankrol FN65 (4,5g) (ethoxylated alkylphenol sulfonate emulsifier) is 6
00g of water was dissolved. The pH was adjusted to 7.8 with a dilute solution of sodium hydroxide and the solution was stirred for 30 minutes. 2 m 12 of tertiary dodecyl mercaptan (chain transfer agent) was added to this solution. 1 g of potassium bersulfate (initiator) was dissolved into the mixture.

A monomer blend consisting of butyl acrylate (384 g) and ethylene glycol dimethacrylate (EGDM) (16 g') was added to the emulsifier/initiator solution.

The temperature was raised to 85°C and held for 5 minutes. The heat source was then switched off.

The remainder of the monomer blend described above was added at a rate sufficient to maintain a temperature of 85°C. Monomer addition is 5
Finished in 0 minutes. 85 for 30 minutes after completion of monomer addition.
℃ temperature was maintained. The latex is then cooled and
filtered. The particle size of the latex was 110 nm.

Step 2: Production of shell/core polymer The equipment used was the same as in Example 1.

500g of core latex contains potassium bersulfate (2g)
was mixed with water (450 g) in which .

This mixture was stirred for 30 minutes under nitrogen atmosphere.

A monomer blend consisting of methyl methacrylate (240 g), butyl acrylate (>60 g) and EGDM (3 g) was made. The temperature was raised to 80 °C and maintained for 5 minutes before the heat source was switched off. The monomer blend was The monomer addition was completed at a rate sufficient to maintain the temperature at 80°C.The monomer addition was completed in 1 hour.After the addition of the entire monomer blend was completed, the volume temperature was increased to 80°C for 1 hour.
was maintained. The latex was cooled and filtered.

The polymer was isolated from the latex by the freeze-thaw method. The sample molded from this polymer powder was 65
It showed a Shore hardness of . Tg of polymer powder is 69℃
was measured.

The produced polymer powder was mixed with methyl methacrylate monomer in a ratio of 3:1 and also with 0.5% benzoyl peroxide relative to methyl methacrylate monomer. This composition was formed into a dental prosthesis by injection molding using the method and apparatus described in British Patent Application No. 2,159,457. Molding was carried out at a temperature of 110-115° C. under a polymer surface pressure of 300-350 pounds per square inch for 90 minutes, followed by controlled fan cooling for 30 minutes. The resulting denture is l1oun
The impact resistance value measured by the dfield method is 0.
17, Shore hardness is 75. Tg was 85°C.

Examples 8-12 The first step of Example 7 was repeated to obtain a crosslinked polybutyl acrylate core polymer emulsion. A sample of this emulsion was used as the second emulsion in Example 7.
The process described in Steps was used to make a series of core/shell polymer emulsions having the compositions set out in Table 1 below. Each core/shell polymer was isolated as a powder, mixed with methyl methacrylate and an initiator, and formed into a denture plate as described in Example 7. The impact resistance values of this plate according to the Hounsf 1eld method are listed in Table 1.

Example 13 (a) Preparation of inner core emulsion 75 parts of methyl methacrylate, 25 parts of butyl acrylate and 1 part of EGDM are mixed into 150 parts using the process described in the first step of Example 7. Emulsion polymerization was carried out in water at a temperature of 80°C.

The emulsion formed had a particle size of 119 parts m.

(b) Preparation of the core polymer Half of the emulsion made in step (a) above is mixed with a solution of potassium bersulfate and butyl acrylate (192 parts) and EGDM (8 parts) are added to the solution of Example 7. 2
Copolymerization was carried out at 85° C. using a step process. The emulsion formed consisted of particles having a cross-linked butyl acrylate layer surrounding a core of methyl methacrylate copolymer. The particle size of the emulsion was 222 parts m.

(C) Preparation of core/shell polymer A portion (20 parts) of the emulsion was mixed with potassium persulfate solution and methyl methacrylate (
60 parts), butyl acrylate (20 parts) and EGD
M (0.8 parts) was copolymerized using the second stage process of the example. The emulsion formed was 384 parts m
The core/shell polymer had a particle size of .

This polymer was isolated as a powder as in Example 7. Its Shore hardness was 73. The polymer powder is mixed with methyl methacrylate monomer and an initiator;
A denture plate was obtained by injection molding as in Example 7. This denture plate showed superior impact resistance values compared to plates molded from polymethyl methacrylate.

Examples 14-16 Polymer powders were prepared using the process of Example 13. Inner core, cross-linked polybutyl acrylate layer,
The compositions of the shell polymers were the same as those described in Example 13, but only the ratio to the polymer layer was changed as shown in Table 2. All polymer powders were injection molded with methyl methacrylate to obtain denture plates with high impact resistance values. The samples were ranked in the following order for impact resistance values: Examples 14>16>13>15.

EXAMPLE 17 Reactions were carried out in a 3I1 reaction flask equipped with a cold trap, nitrogen inlet, thermocouple, paddle stirrer, and monomer feed.

Perlankrol FN65 emulsifier (4.5 g) was dissolved in 1150 g of deoxygenated water. The pH was adjusted to 7.8 with diluted sodium hydroxide solution and 2 ml of tertiary dodecyl mercaptan (chain transfer agent).
was added to this solution. Butyl acrylate (384
g) and EGDM (16g')
of the monomer blend was added to the emulsifier solution. The temperature was raised to 60° C. and an initiator solution (1.0 g ammonium bersulfate dissolved in 10 g water) was added to the emulsified monomer mixture. The temperature rose to 85°C due to the heat of reaction and the heat source was switched off.

The remaining monomer blend was added at a rate sufficient to maintain a reaction temperature of 85°C. After the addition of the monomer blend was completed in 60 minutes, the temperature was maintained at 85° C. for 15 minutes, and the polymerization was 95% complete.

Fresh initiator solution <4 g AP dissolved in 20 g) was added and after 5 minutes the second monomer blend (total of 4 g AP) was added.
80g methyl methacrylate.

120g butyl acrylate and 6g EGDM)
was added at a rate sufficient to maintain the reaction temperature at 80°C. The addition of the sucrose was completed in 60 minutes and the temperature was maintained at 80° C. for 60 minutes to achieve complete conversion.

The emulsion was cooled, filtered and the polymer isolated as in Example 7. This polymer was injection molded with methyl methacrylate as in Example 7 and
A denture plate with properties similar to those of the denture plate was obtained.

Example 18 Crosslinked poly(butyl acrylate) core polymer particles were made as described in Example 7. Example 7
MMA, BA, EGDM using the second step process of
The core/shell polymer particles were prepared with a second stage monomer composition of 80:2022 by weight and a 35:65 ratio of core polymer to shell polymer. The particle size of the polymer powder formed is 145 nm and the Tg is 75
It was ℃.

This polymer was mixed with methyl methacrylate monomer in an Ivoclar Cap-vibrator at a 2:3 weight ratio of polymer to monomer to form a gel. This gel was molded using the process of GB Patent Application No. 2,159,427 as well as GB Patent No. 1,442,041 to obtain a denture plate. In both cases, l1
Impact resistance value by unsfield method is 0, 11
The denture plate had excellent resistance to impact with a Tg of 100°C.

Reihaku below

Claims (1)

[Claims] 1. A polymer characterized in that one or more polymer particles consisting of a first polymer insoluble in a solvent encapsulated in a second polymer soluble in a solvent are dispersed in a solvent. Method for producing dispersion liquid. 2. The polymer particles are core/shell polymer particles consisting of a shell of a second polymer surrounding a single core of a first polymer.
The method described in Section. 3. The method of claim 1, wherein the polymer particles are one or more core particles encapsulated within a matrix of a second polymer. 4. The method according to any one of claims 1 to 3, wherein the core particles have a particle size of 0.5 μm or less. 5. Any one of claims 1 to 4, wherein the first polymer is prepared by emulsion polymerization.
The method described in Section. 6. The method of any one of claims 1 to 5, wherein the first polymer comprises at least 70% by weight vinylidene chloride. 7. Any one of claims 1 to 5, wherein the first polymer comprises at least 70% by weight of an alkyl acrylate having 3 to 6 carbon atoms in the alkyl group. method described in. 8. The method according to any one of claims 1 to 7, wherein the polymer is a crosslinked polymer. 9. The core particles include particles of a first polymer, particles of a block copolymer having at least one segment replaceable with the first polymer, and at least one segment replaceable with the second polymer. 9. A method as claimed in any one of claims 1 to 8, characterized in that the method comprises: 10. The method according to any one of claims 1 to 4, wherein the first polymer is a silicone elastomer. 11. The method of claim 6, wherein the second polymer is a fiber-forming vinylidene chloride copolymer having a lower vinylidene chloride content than the first polymer. 12. The method according to any one of claims 1 to 9, wherein the second polymer is a fiber-forming acrylonitrile polymer. 13. The composition is an acrylonitrile-based composition comprising first polymer particles dispersed in a solution of a fiber-forming acrylonitrile polymer in a solvent, the first polymer particles being insoluble in the solvent. Fiber-forming polymer composition. 14. Claim 13, wherein the first polymer particles have a particle size of 80 nm to 1 μm.
Compositions described in Section. 15. Claim 13 or 14, characterized in that the solvent is an aqueous solution of sodium thiocyanate.
Compositions described in Section. 16. The composition according to claim 13 or 14, wherein the solvent is dimethylformamide. 17. A method for forming acrylic fibers, characterized in that the fiber-forming polymer composition according to claim 15 is spun into a further diluted aqueous solution of sodium thiocyanate. 18. A method for forming acrylic fibers, characterized in that the fiber-forming polymer composition according to claim 16 is dry-spun. 19. A flame-retardant acrylic fiber, characterized in that the fiber comprises particles of vinylidene chloride polymer dispersed within a continuous phase of acrylonitrile polymer. 20. The method according to claim 1, wherein the solvent is a polymerizable monomer. 21. The method according to claim 20, wherein the solvent is a methacrylate ester. 22. A molding composition used for the manufacture of denture plates comprising a mixture formed from a polymer powder and a methyl methacrylate monomer, said polymer powder having from 3 to 6 carbon atoms in the alkyl group. Composite particles having a hard acrylic polymer shell consisting of at least 60% by weight polymerized methyl methacrylate surrounding a core comprising a rubbery acrylic polymer that is a cross-linked polymer of alkyl acrylate, said hard acrylic polymer comprising methyl methacrylate. A molding composition characterized in that the rubbery acrylic polymer core particles are at least partially dissolved in the monomer, while the core particles of the rubbery acrylic polymer are substantially insoluble in the methyl methacrylate monomer. 23. The hard acrylic polymer has a glass transition temperature of 60-85°C, 70-85% by weight of methyl methacrylate and 3-6 carbon atoms in the alkyl group.
23. A composition according to claim 22, characterized in that it is a copolymer with % by weight of alkyl acrylate. 24. The rubbery acrylic polymer has at least 70
% by weight of butyl acrylate and 2-8% by weight of a crosslinking monomer having two or more polymerizable unsaturated groups. composition. 25. Claims 22 to 24, wherein the core comprises an inner core of cross-linked methyl methacrylate copolymer and an outer core of a rubbery polymer.
A composition according to any one of paragraphs. 26, the weight ratio of core polymer to shell polymer is 10
26. The composition according to any one of claims 22 to 25, characterized in that the ratio is in the range of :90 to 50:50. 27. The composition according to any one of claims 22 to 26, characterized in that the weight ratio of polymer powder to methyl methacrylate monomer is in the range of 1:1 to 4:1. thing. 28. The composition according to any one of claims 22 to 26, characterized in that the weight ratio of polymer powder to methyl methacrylate monomer is in the range of 1:2 to 1:1. thing. 29. A molded article in which the molding composition according to claims 22 to 28 is injected into a mold for a denture plate, heated so that methyl methacrylate is polymerized, and the composition is polymerized. A method for molding a denture plate, characterized in that at least a part of the heating is performed at a temperature higher than the glass transition point of the molded product. 30. The mold for the denture plate has means for injecting an additional molding composition, and claim 22
The method according to claim 29, characterized in that the molding composition according to any one of claims 2 to 28 is additionally injected during the molding and polymerization.