US2058786A - Light protective wrapper - Google Patents

Description

Patented Oct. 27,. 1936 PATENT OFFICE LIGHT PROTECTIVE WRAPPER Dudley H. Grant, Berkeley Heights, N. J., assignor to Stanco Inc., a corporationof Delaware No Drawing.

Application February 2, 1931, Serial No. 513,058

. 2 Claims. (01. 91-68) This invention relates to light protective wrappers and the process of making the same and will be fully understood from the following description.

I have discovered that wrappers of paper, cloth, transparent films of cellulose or hydroxycellulose (made by precipitation from viscose, cuprammonium or other cellulose solutions), gelatine, acetylcellulose, nitrocellulose, pyroxylin or other thin flexible material, such as are used to wrap commodities which may be injuriously affected by sunlight .or other actinic light, may be rendered wholly or partially impervious to such light by means of substantially colorless substances having the property of absorbing light waves of short wave length.

The following substances may, for example, be used in the preparation of light protective wrappers according to the present invention: quinine and its salts, aesculin, methyl esters of naphthalene carboxylic acids, salts of naphthol sulfonic acids, phthalic acid salts, and in. general protective substance to the solvent used in the manufacture of the pyroxylin material. Such or similar methods may be used with other thin 40 flexible materials to incorporate the light protective ingredient. Laminated sheets of two or more layers of the same or difierent materials,

one or more layers containing the protective substance, may also be used.

. The amount of the ingredient added depends on the substance and also on the degree of light protection desired and correspondingly may be varied within large limits.

The following examples will serve to illustrate 60 my process and the method of carrying it out.

Example 1 Sheets of paper, preferably the translucent paper known in the trade as glassine, are coated on one 'or both sides with a lacquer composed 5 approximately as follows:

Per cent FYIOXylin 3 Amyl acetate or other medium boiling solvent. 5-25 10 Aesculin 0.5-5 Monoethyl ether of ethylene glycol or other blending agent 3-10 Ethyl acetate, acetone or other low boiling solvent 10-30 15 Castor oil or other plasticizer 2- 5 Benzol, toluol, naphtha or other diluent 30-70 For aesculin in the above example may be substituted quinine alkaloid, quinine ricinoleate, linoleate or other quinine salt compatible with the lacquer film, phenanthrene, anthracene, or other substances of the types specified above.

Example 2 In the manufacture of thin sheets of cellulose or hvdroxycellulose by regeneration (coagula-' tion) from solutions of viscose, some of the lightprotective materials specified above may be incorporated with the viscose solution before 00- 'agulation. Among such substances may be mentioned the sodium salts of carboxylic or sulfonic acids derived from naphthalene, anthracene; phenanthrene, fiuorene and other conjugated hydrocarbons. '35

The transparent sheets of regenerated cellulose or hydroxycellulose, after washing and drying, may also be coated with lacquers as described in Example 1.

Example 3 V 40 1% to 20%. The sizing solution is then applied to paper or cloth.

Example 5 Transparent films, wrappers, caps, capsules, etc., made of gelatine, gelatine-glycerine, formaldehyde-gelatine or chromated gelatine have water-soluble protective substances such as quinine bisuli'ate, sodium naphthalene sulfonates or other salts of sulfonic or carboxylic acids of conjugated hydrocarbons, added to the gelatine solution in amounts of 1% to 30% before drying coagulating or exposing to light.

Example 6 Example 7 To paper pulp in the heater is added a solution capable of furnishing a water-insoluble lightprotective substance of the classes mentioned above, when such solution is decomposed by subsequent addition of another reagent such as acid or alkali, and the protective substance is thereupon precipitated in intimate contact with the paper fiber, remaining in the finished paper. For example, to 1,000 lbs. of paper stock inthe pulp state in the beater is added '10 lbs. of quinine hydrochloride dissolved in water. To the mixture is then added an amount of sodium resinate, stearate, etc., equivalent to the quinine salt or in slight excess, thereby precipitating quinine resinate, stearate, etc., in the pulp. For sodium resinate or stearate may be substituted any alkali salt of an acid of which the quinine salt is insoluble in water.

Similarly, water-insoluble protective substances of acid nature, such as naphthalene carboxylic acids, may be precipitated in the pulp by adding their alkali salts to the pulp and then acidifying it with hydrochloric or other acid. In this case. I find it advantageous to combine the sodium salts of naphthalene carboxylic acids (or carboxylic acids of other conjugated hydrocarbons) with sodium resinate. Subsequent acidification then precipitates the carboxylic acids mixed with rosin acids, which aid in their fixation in the paper fiber. For example, 15 lbs. of sodium naphthalene beta-carboxylate and 20 lbs. of sodium resinate are dissolved in water containing 1,000 lbs. of paper stock in the beater. After thorough mixing, 2 gallons, or a suitable slight excess, of hydrochloric acid is gradually added. In either case, when the pulp passes to the paper machine, it retains the light-protective substance intimatelymixed with the fiber, and remaining in the finished paper.

Having thus described my invention and the method of carrying it out what I claim is:

1. A thin, flexible transparent wrapper of regenerated cellulose, for articles tending to deteriorate if subjected to actinic light, said wrapper comprising a colorless substance adapted to prevent the passage of objectionable amounts of such light, in which the colorless substance is a coating having the following approximate composition:

Per cent Pyroxylin 3 Amyl acetate or other medium boiling solvent 5-25 Colorless absorber of actinic light 0.5- 5 Monoethyl ether of ethylene glycol or other blending agent Ethyl acetate, acetone or other low boiling solvent 10-30 Castor oil or other plasticizer. 2- 5 Benzol, toluol, naphtha or other diluent 30-70 2. A wrapper according to claim 1 in which the colorless absorber of actinic light is aesculin.

DUDLEY H. GRANT.