JPS6031849B2 - Method for recovering nitrile polymer solids from latex - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for isolating and recovering latex solids, particularly substantially water-free and uncontaminated polymers in the form of particles of a desired predetermined size. It concerns the method of collecting the

In summary, it involves a method for recovering nitrile solids from latex by mechanically shearing the latex to form a paste, then shaping, and contacting the shaped paste with hot water soot. In the recovery of resin from latex solids, it is desirable to carry out the process in such a way that the recovered solid is the desired resin. i.e. substantially free of moisture and contaminants;
For example, it is desirable to perform a resin recovery process that is free of emulsifiers, electrolytes, and water-soluble salts, and that is in a particle size and shape suitable for subsequent processing operations on the resin. It is also desirable to carry out the recovery of resin from the latex solids in a manner that is as economical as possible, particularly with respect to time and cost. Many techniques are known for recovering resin solids from latex, with much of the prior art relating to the natural rubber, synthetic rubber and resin sectors.

A well-known technique for recovering polymer solids using electrolytes, alcohols, etc. is coagulation. However, in many cases the coagulated polymers have a wide range of viscosities and contain significant amounts of very fine particles that are extremely difficult to purify and recover using conventional filtration or sieving equipment. US Patent No. 32
No. 48,455 and No. 3,345,430, a polymer latex is first coagulated in part with an electrolyte to form a paste, the paste is then molded and the molded mass is recovered at a high temperature such as the heating strain temperature of the resin. It has been proposed to produce dried polymers of controlled particle size by passing them through an aqueous medium maintained at a temperature.

Such methods include adding an electrolyte to a polymer latex and washing the electrolyte and contaminants from the polymer in an aqueous soot. The present inventors shear a latex of nitrile-rich polymer, optionally at elevated temperatures and in the absence of an electrolyte, to form a paste, then shaping the paste, and forming a high A process has been discovered that can be used to process nitrile polymers by passing them through aqueous soot held at temperature.

The present invention can be practiced without the use of electrolytes required in the prior art, which is unexpected to those skilled in the art. One object of the present invention is to provide a new method of latex solids recovery that does not require conventional electrolyte coagulants and does not require adjustment of the solids or water content of the latex.

Another object of the present invention is to provide a method for recovering substantially water and electrolyte-free polymer having controlled particle size and particle size distribution from a polymer latex.

Polymeric latexes useful in this invention include polymers obtained by emulsion polymerization of a large amount of olefinically unsaturated nitrile and optionally other monomer components in the presence of a preformed rubber.

In the method of the present invention, the polymer latex is cut through known shearing devices (s) with nozzles, orifices, or other confining mechanisms.
shearing in a hearing device such as a colloid mill, Waring blender, high speed propeller mixer, or pump to produce a paste with a consistency similar to that of toothpaste.

This paste is applied to one or more molding units, preferably one
producing a molded unit with a minimum cross-sectional area of about 0.01 inch and holding the molding base at an elevated temperature, preferably near or above the heat strain temperature of the polymer (ASTM Test D-648-56); Heat in an aqueous medium. This hot water treatment serves to harden the molded paste to the same particle size and solid consistency of paste shape that the paste had before entering the bath. The cured particles can then be easily recovered and, if desired, washed and dried to leave resin particles substantially free of attached moisture and electrolyte. Shear (
The term "shear" refers to an internal force that is tangential to the surface on which it acts, and is a shear force.

Shear is the effect or stress resulting from applied forces in a mirror direction that causes the two scales of the latex body to slide relative to each other in a direction parallel to the contact surfaces. The present invention also includes extruding the paste through narrow orifices to form thin (eg, 1/100 to 1/4 inch diameter or larger, depending on orifice size) threads or strands.

Such combs or strands are of the same composition as the paste, which combs or strands are a homogeneous mixture and include the total solids content and water content of the latex that was sheared to produce the paste. In one implementation of the invention, the resulting formed strands or strands of shear-solidified latex paste are gently dropped into hot water. The resulting laminated particles can be easily washed, separated, and dried effectively without losing particle shape.

Typically, the latexes (or blends of latexes) used in the present invention will contain between 20% and 45% solids and have an average particle size ranging from 500 to 3000 Angstroms.

The solids content of the base is substantially the same as the mass content of the starting latex. The production of shaped granular materials substantially free of fine particles can be produced by the method of the present invention, whereby the initially shaped particles have sufficient structural strength and are suitable for syneresis (hot water agglomeration or hardening) operations. or remain intact between washes. The above method usually allows efficient cleaning since large particles are difficult to clean.

This means that the drying work can be done quickly. Excessively large particles take a long time to dry and tend to have a hard exterior. Also, the long or harsh drying conditions required for excessively large particles tend to degrade the polymer during drying. Polymers useful in this invention include a large amount of an unsaturated mononitrile, such as acrylonitrile, and optionally a small amount of other monovinyl polymers, in a preformed diene rubber (a copolymer or homopolymer of conjugated diene monomers). This is a polymer obtained by polymerizing in an aqueous tank in the presence of

The ester of the olefinically unsaturated carboxylic acid used in the production of the polymer has the formula
to 6 alkyl groups).

Examples of such esters of unsaturated carboxylic acids are methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, amine acrylate, hexyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, methacrylate. butyl methacrylate, amine methacrylate, hexyl methacrylate, methyl Q-chloroacrylate, ethyl Q-chloroacrylate, and the like. The most preferred esters for preparing the polymers of this invention are methyl acrylate, ethyl acrylate, methyl methacrylate, and ethyl methacrylate. Q- useful for producing the polymer of the present invention
The olefin is an olefin having 4 to IN carbon atoms and having the following formula (wherein RII and R12 are an alkyl group having 1 to 7 carbon atoms).

Particularly preferred Q-olefins are isobutylene, 2-methylbutene-1,2-methylbentene-1,2-methylhexene-1,2-methylhebutene-1,2-methyloctene-1,2-ethylbutene-1,2-propylbentene-1, etc. The most preferred is isobutylene. Conjugated diene monomers useful in making the polymers of this invention include butadiene-1,3, isobrene, chlorbrene, bromobrene, cyanoprene, 2,3-dimethyl-butadiene-1,3-2-ethyl-butadiene-1,3,2, 3-diethyl-butadiene-1,3 and the like.

The most desirable are butadiene-1,3 and isoprene from the viewpoint of easy availability and excellent copolymerizability. The olefinically unsaturated nitriles useful in the production of the polymers of the present invention are Q,3-olefinically unsaturated nitriles of the following formula: It is an unsaturated mononitrile.

Examples of such nitriles are acrylonitrile, Q-chloroacrylonitrile, q-fluoroacrylonitrile,
Methacrylonitrile, ethacrylonitrile, etc. The most preferred nitriles are acrorylonitrile, methacrylonitrile and mixtures thereof. Examples of other monovinyl monomer components that can be copolymerized with the nitriles useful in the production of the polymers of the present invention include one or more olefinically unsaturated carboxylic acids, 'Reether, Q-olefin, vinyl aromatic monomer, etc.

Vinyl ethers include methyl pinyl ether, ethyl pinyl ether, propyl vinyl ether, butyl vinyl ether, methyl isoprobenyl ether, ethyl improbenyl ether, and the like. Most preferred are methyl pinyl ether, ethyl vinyl ether, propyl pinyl ether and butyl vinyl ether. Vinyl esters include vinyl acetate, vinyl propionate, pinyl butyrate, and the most preferred is vinyl acetate.

Vinyl aromatic monomers include styrene, Q-methylstyrene,
Examples include vinyltoluene and vinylxylene, with styrene being the most desirable.

The method for producing the polymer of the present invention is disclosed in U.S. Patent No. 3,426,102,
No. 3,586,737 and U.S. Patent Application No. 22,297.

Preferred polymers of the present invention include at least 5% smoke of at least one nitrile of the formula (wherein R is as previously defined);
and Esther of the song '1' formula (where RI and R2 are as defined previously), '
2} where RII and R12 are as defined above, {3}
a vinyl ether selected from the group consisting of methyl vinyl ether, ethyl vinyl ether, propyl vinyl ether, and butyl vinyl ether; [4] at least one selected from the group consisting of vinyl acetate and styrene;
5% by weight of the seed monomer based on the total weight of ■+{B}
■ 10 parts by weight of a monomer mixture of 10 {B} with amounts up to 50% by weight of the polymerized conjugated gene monomer, 10% by weight of the polymerized conjugated monomer, 0% of the other polymerized monomers, and 5% by weight.

a conjugated diene monomer selected from the group consisting of isoprene and butadiene; optionally a monomer selected from the group consisting of styrene and a nitrile of the formula (wherein R is as previously defined); A rubber-like polymer prepared in advance from 1 to 4 was polymerized in the presence of 4 parts by weight.

It is preferable that the amount of the component is about 60% to 9% by weight based on the total weight of A and B. The rubber-like polymer [C} must contain at least 5% by weight of the conjugated gene monomer, and preferably contains 60 to 9% by weight of the conjugated gene monomer. The polymers of the present invention can be prepared in a manner that achieves the desired balance between impact strength, flexural strength, tensile strength, processability, heat strain temperature, and that other ingredients and additives are present without undesirable adverse effects on the final article. , pigments, colorants, stabilizers, etc., which are well known to those skilled in the art.

The polymer used in the method of the present invention is thermoplastic and can be molded by various conventional methods used for molding known thermoplastic polymers, such as extrusion, grinding, molding, pultrusion, blowing, etc. It can be made into a good article.
The polymers obtained from the process of the invention have excellent solvent resistance, cold resistance, and excellent impact strength (when rubber modified) and have low permeability to gases and vapors. It is extremely useful in the packaging industry due to its
It is particularly useful for making bottles, films, sheets, boxes and other containers for liquids and solids. Next, examples of the present invention will be shown.

All parts used in the examples refer to parts by weight unless otherwise indicated. Example 1A A rubber latex was prepared using the following ingredients by polymerization with continuous lighting at 45 qo in the substantial absence of oxygen.

Ingredients: Acrylonitrile 30 butadiyune 1,3 60 ingredients
Part emulsifier (OAFACRE-610) *2
．． 4 Azobisisobutyronitrile 0.3
t-dodecylmercabutane 0.5 water
200* Trade name of an emulsifier sold by General Aniline Film Company, formula R-0-(CQC day 201) nP03M
2 and the compound of the formula [R-○-(CQCH20-)2
P02M, in which n is a number from 1 to 40, R is an alkyl or alkali group, particularly preferably a nonylphenyl group, and M is hydrogen, ammonia or an alkali metal.

The pH of the mixture was adjusted to about 8 using KOH before starting the reaction.
It was adjusted to

Polymerization 22. Conversion rate of monomer is about 92% after hours of operation.
, the total solids content of the latex produced was about 33.1%. B A resin having impact resistance and gas permeation prevention properties was produced by polymerizing a mixture of the following components.

Ingredients: Acrylonitrile 75 ingredients
Part Methyl Acrylate 25 Solid in the form of latex (prepared in A above)
9 weeks potassium sulfate 0.
06 Emulsifier (OAFACRE-610) 3
．． 0n-dodecyl mercabutane 1.0 ethylenediaminetetraacetic acid 0.05 water
200 pH was adjusted to about 7 with NH40 days.

Polymerization was carried out at 60° C. for 5 hours in the substantial absence of oxygen to give 9
Latex was produced at a conversion rate of 1%. The latex obtained from the polymerization was kept in a container containing a high-speed mixer throughout the week. Container mixer equipment includes Waring blender, isoline, dispersion machine (in-li
nedispemator or high shear
-shear) mixing device. The latex remained inside the container for an average of about 15 seconds. The product from the container mixer equipment had a consistency similar to toothpaste. This product was then extruded through a narrow orifice (1/16 inch diameter) plate to produce thin combs or strands. Next, I dropped this stick into hot water (80 points 0) where it was being gently worshiped by a hawk. The bar remained in the hot water for approximately 10 minutes. The resulting polymer was washed, dried and compression molded into bars at 150 oo. The molded bar was clear and had the following materials: Izod impact value is 1.2 higher per inch of notch. Lb, ASTM heating strain temperature is 6900 (ASTM D-648-56 #2
64) and 75q○ (ASTMD-648-56, #
66). The polymer was easily mixed in a Brabender Blasticorder and had a work reading of 115 n-g after 10 minutes at 230 DEG C. and $rpm in a Brabender-1 Blasticorder. When a sample of this polymer was compression molded into a sheet, the water vapor permeability of this sheet was 4.51 mils/100 mils/2 mils (ASTM).
The temperature was 90% relative humidity, 100o F). The oxygen permeability of this sheet is 0.6cc/mil/10
0 form/24 hours/atm (ASTMD-1434). Also, this sheet has a rating of 6.4 haze units.
It had a frosting index of nits. Frost index is obtained by measuring the light or haze refracted through a piece of sheeting. 5000 and 100 sheets with
% relative humidity for 16 hours, at which time haze was remeasured. The difference in haze readings is the frost index. Haze reading is Hunter Laboratories Color Difference Meter Model D-
It was done on 251F. C Steps A and B above were repeated in the same manner except that the resin obtained from the polymerization was coagulated with dilute aluminum sulfate solution and isolated from the latex (which is outside the scope of the present invention).

The resulting resin was then shaped into fine twills or strands (1/16 inch in diameter) and then dropped into gently flowing hot water (80 q0). 10 of these hayashi
It was left in hot water for a minute. The resulting polymer was washed, dried and compression molded into bars at 15,000. The molded bar was transparent and had the following physical properties. Izod impact value is 1.5 mm per inch of notch. but. Lb, ASTM heating strain temperature is 65
It was qo and 7 pi○. The polymers are easily mixed in a Prabender Plasticorder and have a work reading of 1 after 10 minutes at 230°C and 38pm in a Plasticorder.
It was 15 enemies. Samples of this polymer were compression molded into sheets. The water vapor transmission rate of the sheet is 5.64 pm/
mil/10 m2/2 cape time (ASTMR-90 9
0% relative humidity, 100o F). Oxygen permeability is 0.6cc/mil/105n2/24 hours/atm (
ASTM D-1434). The sheet had a frost index of 20.6 haze units and a much deeper yellow color than that of B above. Example 2 A resin was produced and isolated using the methods of Examples IA and IB, except that in Step B, 8 parts of acrylonitrile and 20 parts of methyl acrylate were used instead of 75 parts of acrylonitrile and 25 parts of methyl acrylate. did.

The Izod impact value of the final resin is fantastic per inch. Lb, ASTM heating strain temperature is 80℃, Brabender
The plasticorder torque was 125 mm.
Example 3 The resin was prepared using the methods of Examples IA and IB, except that in step B, 70 parts of acrylonitrile, 17 parts of methacrylonitrile, and 13 parts of methyl acrylate were used in place of 75 parts of acrylonitrile and 25 parts of methyl acrylate. produced and isolated.

The Izod impact value of the product is $t. per inch of notch.
Lb, ASTM heating strain temperature was 770, Brabender Plasticorder torque was 160 h. Example 4 A 60 oo copolymer of acrylonitrile and methyl acrylate was prepared with substantially complete conversion from a mixture of the following components.

Ingredient Part Water 156 Acrylonitrile 75 Methyl acrylate
25 Emulsifier (GAFACRE-610)
3 Modifier (Mercapta Q-43
) * 1.05 ammonia
0.06 component part chelating agent (mpe ship K-4-100) ※※0.05※ Tetraester of pentaerythritol and beta-mercaptopropionic acid ※※ Polymerization of tetrapotassium salt of ethylenediaminetetraacetic acid with a conversion rate of approximately 99% A latex containing approximately 31% solids was obtained.

Pour about 250 ml of this latex into a glass container, and
Warmed to 8°C. This warm latex was added to a Waring blender and blended with a high speed blender blade to form a paste. Apply this paste to the orifice (1/1
6 inch diameter) to extrude it through the strand.
nd) was produced and placed in gently heated hot water (80 qo) and left in the hot water for about 10 minutes. Some of the resulting polymer was washed and dried, 15
000 to make a bar. The Izod impact value of this test bar was 0.37 ft. per inch of notch. Lb
The Brabender Plasticorder torque was 130 mm. Example 5 A resin was prepared by polymerizing the following components.

Ingredients Partially distilled water 250 Emulsifier (
Nail ipaIC0436) * 1.5 Acrylonitrile 75 Methyl acrylate 25 Limonene dimerkabutane
0.5 (N ratio)2S2Q
O. 06 Butadiene
12.0* Sulfated
) Ammonium salt of nonylphenoxypoly(ethyleneoxy)ethanol All of the above ingredients except butadiene were charged into a reactor and nitrogen was blown in to create oxygen.

Polymerization was continued for 60 minutes until 89.5% of the monomers were converted to polymer.
It was carried out while praying at ℃. At this point, all of the butadiene was added and the polymerization continued until the final conversion was 93%. The resin was recovered from the latex by the method of Example IB. The final resin had the following physical properties. Izotsu impact value 6.0 per inch of notch. $t. Lb Brabender Plasticcorder Torque 1890h-Evening

Claims (1)

[Claims] 1. In a method for recovering nitrile polymer solids from a nitrile polymer latex obtained by emulsion polymerization of a large amount of olefinically unsaturated nitrile and a small amount of other monomer components in the presence of a pre-prepared rubber. , applying shear forces to the latex in a shearing device selected from pumps, colloid mills, Waring blenders, and high speed propeller mixers having nozzles, orifices or other control devices without a coagulation process that adds electrolytes to the latex. The paste is sheared until a homogeneous self-shaping paste with a consistency similar to that of toothpaste is obtained by adding only A method for recovering nitrile polymer solids from the latex, comprising curing the latex and then recovering the molded units.