US2385879A

US2385879A - Composition for surgical and medical preparations

Info

Publication number: US2385879A
Application number: US402236A
Authority: US
Inventors: Carl W Patton
Original assignee: Carbide and Carbon Chemicals Corp
Current assignee: Carbide and Carbon Chemicals Corp
Priority date: 1941-07-12
Filing date: 1941-07-12
Publication date: 1945-10-02
Anticipated expiration: 1962-10-02

Description

Patented Oct. 2, 1945 COMPOSITION FOR SURGICAL AND MEDICAL PREPARATIONS Carl W. Patton, Palisades Park, N. J assignor to Carbide and Carbon Chemicals Corporation,'a corporation of New York No Drawing. Application July 12, 1941, Serial No. 402,236

1 Claim.

This invention relates to molded surgical and medical supports, and has for its objects the provision of an improved cast material which is light in weight, transparent, convenient to apply, non-flammable, and resistant to water, acids, alkalies, alcohol and aliphatic hydrocarbon liquids. By means of my invention direct support can be provided for injured limbs, or movement of an injured body member can be restrained until the injured member has healed or improved in strength to such an extent that its support or restraint is no longer required.

The present practice oi; supporting fractured, sprained or otherwiseinjured members of the body involves, besides rigid splints, the use of one of two different types of cast materials, as classified with respect to the manner in which these materials assume a rigid state from a moldable state. One type of cast material, an example .of which is plaster of Paris, consists of a material which is a powder in its molding state, but which is capable of forming a dense, rigid, supporting structure upon being hydrated. The other type of cast material, an example of which is a fabric bandage impregnated with'a solution of cellulose nitrate, consists of a material which is suificiently flexible when wet with solvent to permit its being wrapped about the injured member, but which is capable of forming a supporting cast when the solvent is evaporated.

Cast materials in current use have certain serious disadvantages which are not encountered with the compositions which constitute my ,invention. The materials belonging to the class which depend for their action upon hydration yield casts which are bulky and heavy, andwhich are somewhat attacked by water and acids. Furthermore, these casts are so dense that X-ray pictures of body members enclosed in them can usually be taken only by high voltage technique, and such pictures are less satisfactory than those obtained with low voltage X-rays. The materials belonging to the class which depend for their action upon solvent evaporation are objectionable because of the highly inflammable character of the solvents and dissolved substances, and because of the odor of the solvents employed. Both classes of materials are inconvenient to apply; both require relatively long periods of time for setting to a rigid state; and neither permits visual examination of the injured member enclosed by it.

The material of this invention is not a member of either of the foregoing classes, but depends for its operation upon its novel thermoplastic properties. It has the property of assuming a moldable plastic state at temperatures above room temperatures, but not so high as to cause injury to the patient, and yet it is relatively strong and rigid at room temperatures. My invention comprises a composition of a resinous base material to which a suitable plasticizing material has been added, as will be more iully described herein.

The class of materials embraced by this invention has proved to be superior to the cast materials now in use, and yields supporting casts which are not attacked by any of the substances normally encountered in the use of cast materials. For example, the cast material or this invention exhibits great resistance to water,

acids, alkalies, alcohol and aliphatic hydrocarbon liquids. In addition, X-ray pictures of body members enclosed in the new plastic compositions may be taken with low voltage X-rays, thus assuring a picture of greater clarity and detail. Other advantages include the ease with which my cast materials can be applied, the rapidity with which they become rigid, the cleanliness of their application, involving. as it does, no liquid setting agents, the transparency of the resulting casts which permits visual examination of the injured member while supported within the cast, the non-flammable character of the cast materials, the absence of odors or fumes both in application and in use, the marked reduction in bulk and weight of the casts, and the provision which can be made for ventilation by perforation of the material.

I. have discovered that desirable thermoplastic properties can be imparted to a conjoint polymer or a vinyl ester or an aliphatic acid and a vinyl halide by incorporating certain plasticizing substances with the resin. I preier to use a resinous base material which is a conjoint polymer composed of 5% to 30% or vinyl acetate and to of vinyl chloride in the molecular weight range of 5,000 to 20,000, the average molecular weight being 7,000 to 12,000. The molecular weights are determined from the specific viscosity of dilute solutions of the resin according to Staudingers method;

A considerable number of compatibl plasticizing materials may be used to yield the de sired thermoplastic properties when incorporated in relatively small amounts with this base material. Among these substances are the halogensubstituted hydrocarbons, such as iodoiorm and chlorinated diphenyl; alicyclic ketones, such as camphor and pyronones, as illustrated by dediphenyl phthalate, and trl(paratertiarybuty1- phenyl) phosphate. f Plasticizing materials having melting oints in the rangeirom 40 to 125 C.

are particularly effective for my compositions. I prefer to employ plasticizlng materials of the class comprising the aryl esters of polybasic-acids,

, particularly phosphoric acid, for-the reason that these substances have no objectionable odor and their use involves no fire hazard. Qther plasti cizers which may be used are included inthe following llst:-- a

Cyclohexyl p-t oluene sulionamide Ethyl o-toluene sulfonamide Ethyl p-toluene sulfonamide Chlorinated diphenyls Diglycol sebacate I Ethyl o-benzoyl 'benzoate Diphenyl mono(o-chlorphenyl) phosphate Di(triglycol chlorhydrin) phthalate Di(butoxyethyl) phthalate Tricresyl phosphate Diphenyl butyl ketone Diphenyl mono(tertiarybutylphenyl) phate Diphenyl mono(o-xenyl) phosphate Xylyl heptadecyl ketone The plasticizing materials which I havedescribed materially lower the softening point of the vinyl resins described and permit the resinous base material to be readily molded to any desired form. Advantageous properties of low melting point and high strength and toughness of the plastic compositions can often be secured by using mixed plasticizing agents. Mixtures of triphenyl phosphate and tri(paratertiarybutylphenyl) phosphate are particularly useful in this respect. The addition of liquid plasticizers, such as triethylene glycol di-2-ethyi butyrate, is useful to avoidany embrittlement of the compositions caused by certain solid plasticizing agents. The amount of plasticizer to be employed will vary depending on the particular plasticizer used, but, in general, from about to about 25% of plasticizer-by weight of the composition is necessary to secure the thermoplastic'properties desired.

The compositions described in the following examples will serve to illustrate the formation and use of the cast materials of this invention: Example 1.-A composition containing 84.5 parts by weight of a conjoint polymer resin analyzing 10% to vinyl acetate and 85% to 90% vinyl chloride and having an average molecular weight of 8,000 to 12,000, together with 12.5 parts of triphenyl phosphate and 3.0 parts of triethylene glycol di-Z-ethyl butyrate, possessed good thermoplastic properties. The composition was cast into sheets about a: of an inch. thick by evaporation from an acetone solution. The sheets exhibited a glossy appearance and were so transparent that it was possible to read standard newsprint through them from a distance of approximately eight feet. Ventilation holes about 1; inch in diameter on inch centers were readily drilled through the sheets, and there were no indications of tearing around these holes during the molding operation. The

phos- 'sheets were readily moldable on very short radii at temperatures comfortably endurable to the human body. Upon cooling, the sheets :became hard, rigid, and tough and did not soiten jflt 115 F., a maximum atmospheric temperature.

A second batch-ref the same composition was ar mixed and calendered into thin films, onto cloth and into thicker sheets. These forms may be used as bandages as hereafter described.

Using this techniqueit was found desirable to improve the working properties of the composition by incorporating minor amounts of a release material, such as carnaubawax; a lubrieating material, such as calcium stearate; and a' stabilizing material, such as calcium hydroxide.

Example 2.A second composition contained 80.7 parts by weight of a conjoint polymer resin analyzing 10% to 15% vinyl acetate and 85% to 90% vinyl chloride and having an average molecular weight of 8,000 to 12.000; together with 0.8 part of a heat stabilizer composed of a mixture of dibutyl tin maleate and dibutyl tin dilaurate in equal proportions, 1.0 part of castor oil, 05 part of stearic acid, 5.0 parts of triphenyl phosphate and 12 parts of tri( paratertiarybu tylphenyl) phosphate. This composition was more pliable at temperatures ranging from the maximum atmospheric to those endurable by the hum-an body than the composition of Example 1, besides being somewhat more workable when the calender forming process was used to form sheets. With these exceptions the physical properties were substantially identical with those of the composition of Example 1.

Example 3.A third composition contained 81.7 parts by weight of a conjoint polymer resin analyzing 10% to 15% vinyl acetate and 85% to 90% vinyl chloride and having an average molecular weight of 8,000 to 12,000, together with 0.8 part of a heat stabilizer consisting of a mixture of dibutyl tin maleate and dibutyl tin dilaur-ate in equal proportions, 1.0 part of castor oil, 0.5 part of phenyl salicylate, a light stabilizer, 10.0 parts of triphenyl phosphate and 6.0 parts of tri(paratertiarybutylphenyl) phosphate. This composition possessed substantially the same physical properties as the composition of Example 2 with the added economy resulting from the replacement of part of the tri(paratertiarybutylphenyl) phosphate content by tri henyl phosphate.

Thermoplastic cast materials can be used in the form of splints, sheets, strips, or fabric impregnated bandages. For example, splints have been made of sheets 1; inch thick and softened to a readily moldable state by immersion in hot water, cooled to a temperature which would not cause the patient discomfort, and then molded by hand manipulation about the region where support was required. Any excess material remaining after fitting can be easily cut away, and the resulting splint secured firmly in place by binding it with surgical adhesive tape or otherwise. The material also has been used in strip form having, for example, the dimensions 2 inches by 0.010 inch, and in cloth-backed form in which the material was calendered or otherwisesecured in a thin layer on a cloth bandage. When strips and coated bandages are used, a small blast of a assure 3 surfaces which are not tacky and do not cause the strips to adhere prematur'ely.- When the strip is heated the adhesive ma'terial melts and penetrates the resin sulilciently to bond successive strip layers securely and thus to prevent lateral slipping and displacement between the layers.

The expression supporting casting materia as used herein refers to a material-which is formed or forma-ble into casts which may be used, for instance, by being applied to a person's body to support an injured member until it is healed.

Many diflerent embodiments of this cast material and variations in its use, other than as described in the foregoing examples are possible without departins from the scope oi the invention.

I claim:

Supporting cast material characterized by Q0 hardness. strensth, rigidity and toughness at room temperatures and at body temperatures combined vinyl chloride content of approxil' mately 10% to 05% by weizht and a plasticizing material which is a mixture or triphenyl phosphate and tri(paratertlarybutylphenyl)l phosphate', said composition beins substantially free from volatile solvent and containing suliicient ll plasticizer within the ranse of about 10% to 25% by weight of plasticiser based on the weight of the composition to live the material the aforesaid characteristics.

CARL W. PA'I'ION.