US3063869A

US3063869A - Novel textile finishing compositions and process for using the same

Info

Publication number: US3063869A
Authority: US
Inventors: Philip B Roth
Original assignee: American Cyanamid Co
Current assignee: Wyeth Holdings LLC
Priority date: 1959-11-05
Filing date: 1959-11-05
Publication date: 1962-11-13
Anticipated expiration: 1979-11-13
Also published as: NL257568A; CH379460A; NL141590B; GB909663A; CH400086A; DE1419364A1; BE596797A; CH1237160A4

Description

United States Patent )fltice 3,063,869 NOVEL TEXTILE F ISHING COMPOSITIONS AND PROCESS FOR USING THE SAME Philip B. Roth, Somerville, N.J., assignor to American Cyanamid Company, New York, N.Y., a corporation of Maine No Drawing. Filed Nov. 5, 1959, Ser. No. 851,008

16 Claims.

relates to compositions comprising uron resins and other thermosetting aminoplast resins and in particular, melamine formaldehyde resins.

In the finishing of cellulose containing textile materials to impart shrinkage control when scorched subsequent to chlorine bleaching.

In addition, the disadvantages associated with chlorine retention during bleaching have been largely overcome by employing novel melamine resins alone or in combination with dimethylol ethylene urea resin. In general, with certain of these improved resinous compositions, yellowing due to chlorine bleaching is at an acceptable minimum when the bleaching occurs after strong acid treatment. Further, these finishes are resistant to home laundering and to chlorine damage until they are degraded by acid conditions. For the most part, acid conditions occur during the souring step of commercial laundering. Although souring should be conducted at a pH of 5 and above, many laundries actually sour at a pH as low as 3.5. From the viewpoint of the finisher of resin treated goods, as well as the customer, it is unfortunate that many commercial laundries customarily sour at such low pHs. Use of very acid souring agents, such as hydrofluoric acid, an extra amount of a silico-fluoride or an accidental rise in temperature of the souring medium are all sufficient to degrade the resinous finishes customarily used on 3,063,869 Patented Nov. 13, 1962 wrinkle resistant and wash and wear" fabrics. These include the commercially available melamine formaldehyde,

urea formaldehyde and ethylene urea formaldehyde resin finishes.

It is an object of the present invention to provide novel textile finishing compositions which when applied to cellu lose containing textile fabrics are characterized by a high resistance to the degradative effects of chlorine retention, both with respect to yellowing due to bleaching and with respect totensile strength of bleached 'goods after repeated launderings.

It is a further object of the present invention to provide compositions which may be readily and conveniently prepared and conveniently finishing equipment. i

It is a further object of the present invention to provide cellulose containing textile materials characterized by a wrinkle resistant finish which is resistant to the degradative effects resulting from chlorine retention.

A still further object of the present invention is to provide a novel composition of resins, which composition when applied to textile materials, produces an unexpected or synergistic eifect in the minimizing eflects resulting from These and other invention will become description thereof set forth hereinbelow.

In accordance with chlorine retention.

prises an alkyl-ated uron resin and an etherified methylol melamine resin in relative weight ratios per parts by tile material wherebya wrinkle resistant finish, resistant to the degI-adative efiects of retained chlorine, is obtained.- By the term cellulose containing textile materials, as meant fibers, yarns, fila-.

that term is employed here, it is knitted, woven or nonexample, cotton, viscose rayon, linen, flax, jute, ramie, or other cellulosic material. These cellulosic textile materials may be employed in combination with other known (1936)], or by modifications of said applied from existing textile of the degradative objects and advantages of the present j more apparent from the detailed V the present invention, a water soluble composition of'matter' is provided which come,

as that term is employed Chem. Soc. Japan 11, 248 a oxymethyl) -uron (I) was obtained. This product has the following structural formula:

H BO CHz-N N-CHzO R Hz H:

invention, a reaction prod- ROCHrN NHCHnOR In Formulas I and 11 above, R is a saturated aliphatic group containing from 1 to 4 carbon atoms such as methyl, ethyl, propyl, including normal and isopropyl, and butyl, including normal, iso, and tertiary. Of these, methyl is greatly preferred.

The term distilled, however, should not be construed limiting on the present invention since distillation is but one means of obtaining a uron resin characterized by the quality and purity identified hereinabove and any means whereby a uron resin of comparable characteristics is obtained is contemplated.

, By the term fcrude uron resin, as that term is employed herein, it refers to uron resin compositions con: taining at least 30% of the compound of Formula I, and in addition, significant amounts of the compound of Formula II, as well as other methylol ureas and alkylated methylol ureas. While the crude uron resins are acceptable and highly useful in the present invention, they normally do not produce the outstanding results obtained by employing the distilled uron resins. However, the cost of the distilled uron resins is markedly more than those of the crude products because of comparatively low yields and expensive manipulative operations. Therefore, while the distilled uron resins are superior in the combination of the present invention, their economics render them less attractive than the crude uron resins.

By the expression substantially fully methylolated melamine as that term is employed herein, it is meant a product which contains a minimum of about 5.8 moles of combined formaldehyde per mole of melamine and preferably up to 6 combined moles of formaldehyde per mole of melamine.

By the expression substantially fully etherifield or substantially full alkylated as they and their equivalent terms are employed herein, it is meant that at least about 5.6 of the available methylol groups on the melamine have been reacted with a suitable alcohol as for example, methanol, ethanol, various glycols and glycol ethers such as ethylene glycol, diethylene glycol, propylene glycol, either as the principal alkyl'ating alcohol or as an alkylatiug constituent. Substantially fully etherified or substantially fully methylolated melamine resins may in general be prepared by alkylating or etherifying substantially fully methylolated melamines. These resins may be prepared by one-kettle" or two-kettle processes, i.e., by methylating or etherifying without isolation of the methylol melamine or bymethylolating, isolating the methylol melamine and then 'etherifying the isolated methylol melamine. In general, such resins can be prepared in 4 accordance with the procedure described in US. application Serial No. 732,814, filed May 5, 1958.

The resin blends of this invention demonstrate a surprising synergistic effect, in that the strength loss due to chlorine retention resulting from the use of the blends is less than the strength loss of the individual components thereof. Other resin combinations evaluated would not demonstrate this synergistic efiect. This will be demonstrated hereinafter. Thus, blends of dimethylol ethylene urea and methylated methylol melamine produced results in no way comparable to those achieved by employing the composition of this invention.

The melamine formaldehyde resins of this invention may be those prepared in accordance with the disclosure of U.S. Patent 2,529,856 and may contain a varyingnumber of methylol groups (i.e. combined formaldehyde) of from between 3 and 6 groups and may be etherified or alkylated up to the degree of methylolation. Thus, for example, a trimethylol melamine may be alkylated with up to 3 moles of a suitable alcohol, though it is not essential that full etherification be present. Of the numberous alkylated methylol melamines contemplated by this invention, those characterized as being partially or substantially fully etherified, substantially fully methylolated melamine resins are greatly preferred.

The relative amounts of uron resin and melamine resin employed in the composition of this invention depend to some extent on whether crude or distilled uron resin is employed and the type of melamine formaldehyde resin used. Still further, it may depend upon whether the melamine formaldehyde resin component also contains a resinous material such as dimethylol ethylene urea in significant amount. Generally, larger amounts of the melamine resin are required with crude uron resin than with the distilled uron resin. Also, larger amounts of the melamine resin are required when it is mixed with another resin such as dimethylol ethylene urea. Thus, the effect of the presence of a third resinous component in the composition should be carefully balanced so that the good effects that may be achieved from its presence do not adversely detract from the synergism produced by the combination of this invention.

Considering these variations in 100 parts of resin solids, the uron resin component should comprise from to 5 parts and the melamine component from 5 to 95 parts. Preferably, the uron resin component is present in amounts of from between 65 to 95 parts and the melamine component is present in amounts of from between 35 and 5 parts.

The resin composition of this invention may be applied to cellulosic textile material and, preferably, cotton fabric by any of the well known techniques as for example, spraying, dipping, immersing, padding and the like in such amounts as to apply from between 1 and about 25% and in some instances, higher amounts of the composition of this invention, based on the dry weight of the fabric. Within certain limits, the amount of resin applied depends on the particular type of fabric being treated. Thus, in treating fabric consisting of cotton fibers, the concentration of from 1 to about 25% and, preferably, from between 3 and 10% resin solids based on the dry weight of the fabric are utilized.

Normally, the resinous composition is applied with a curing catalyst or accelerator. The catalyst utilized may be free acid, acid salts, alkanolamine salts, metal salts and the like. The concentration of catalyst employed may range from about 0.1 to about 25% or higher, based on the weight of the resin solids, depending upon the particular catalyst type employed. Thus, for example, from between about 0.1 and about 10% of a free acid, such as phosphoric, tartaric, oxalic or the like, may be employed, while in the case of ammonium chloride amounts of from between 0.5 and about 10% are used. In the case of amine salts, including alkanolamine salts, such as diethanolamine hydrochloride, from about 1.0 to

ddsie about are most useful, while with respect to salts such as magnesium chloride, zinc chloride, zinc nitrate, and aluminum chloride, amounts of between about 5 and have been sucessfully employed. In all instances, the concentration of the catalyst is based on the weight of the resin solids employed.

Following the application of the resin and curing catalyst to the textile fabric, the material is subject to drying and curing operations to etfect the properties of shrinkage control and wrinkle resistance. The drying and curing operation may be carried out in a single step or in separate steps. The temperatures at which the drying and curing operations are eflective vary widely and are influenced to some extent by the type of catalyst employed. Normally, the range of temperature extends from about 180 F. to about 450 F. or even higher. Generally speaking, the time of the drying and/or curing operation is inversely proportional to the temperature employed, and of course is influenced by whether or not separate or combined drying and curing steps are employed.

Generally, when drying and curing is carried out in a combined operation, a time of from about 1 minute to about 10 minutes may be employed at temperatures from about 450 to 250 F., respectively. When the fabric has been dried preliminary to curing, curing times of the order of 5 minutes to about A minute at a temperature of from between 250 and 450 F., respectively, have been successfully employed.

In order to illustrate the present invention, the following examples are given primarly by way of illustration. No specific details or enumerations contained therein should be construed as limitations on the present invention except as they appear in the appended claims. All parts and percentages are by weight unless otherwise clearly designated.

EXAMPLE 1 Preparation of Crude Uron Resin A mixture of 1378 parts (17 moles) of 37% formalin, 12 parts of 50% caustic soda and 240 parts (4.0 moles) of urea were heated at the reflux temperature for minutes (pH 6.65). The solution was concentrated in vacuo to an internal temperature of 7075 0., thereby obtaining 678 parts of residue having 93.9% solids. When about 2500 parts (actually 2530 parts) of methanol and 57 parts of concentrated hydrochloric acid had been added, stirring at room temperature Was continued for 20 minutes (pH less than 1.0). The pH was adjusted to 9.3 with 50% caustic soda, and the solution was concentrated in vacuo to an internal temperature of 65-70 C. The residue was dissolved in 2400 parts of chloroform and the solution was filtered. The solution was then concentrated in vacuo to an internal temperature of .90" C. The residue, amounting to 705 parts, was crude uron resin and contained about by weight of uron.

EXAMPLE 2 Preparation of Distilled Uron Resin A mixture of 60 parts (1.0 mole) of urea, 345 parts (4.26 moles) of 37% formalin and 9.2 parts of barium hydroxide octahydrate was stirred at 94 C. for 10 minutes. After concentrating in vacuo in a steam bath, the viscous residue was dissolved in 800 parts of methanol, and 11 parts of concentrated hydrochloric acid were added. When the solution had been stirred at room temperature for 15 minutes, the pH was adjusted to 8.0 with 9.0 parts of barium hydroxide octahydrate, and the solution was concentrated in vacuo on a steam bath. The viscous residue was mixed with 1490 parts of chloroform and the mixture was filtered. To the resulting solution there was added 700 parts of ether, and the solution was filtered again. This solution was concentrated on a steam bath, first at atmospheric pressure and then in vacuo. The residue was distilled in vacuo using an atmosphere of-nitrogen and a 6-inch Vigreux column. A forerun of 25 parts was discarded. The main fraction, a colorless viscous liquid boiling at 131134 C. at about 2 mm. of mercury pressure and amounting to 34 parts, was distilled uron resin. The residue amounted to 70 parts.

EXAMPLE 3 Resin A=product of Example 2.

Resin B=substantially fully methylated, substantially fully methylolated melamine.

Pad baths were prepared containing 6.25% total resin solids of Resins A and B, alone or in blends at /25, 50/50 and 25/75 solids ratios, respectively. The pad baths also contained 12% of magnesium chloride based on the resin solids in the bath. Five percent resin solids on the weight of the fabric were applied to x 80 cotton percale using an 80% Wet pick-up. Fabrics were dried at 225 F. for 1 minute and cured at 350 F. for 1.5 minutes.

The wrinkle recovery was measured on a Monsanto wrinkle recovery tester following the tentative test method 66-1956 described on page 158 of the 1957 Technical Manual and Yearbook of the American Association of Textile Chemists and Colori'sts, vol. 33.

The chlorine retention test was carried out by tentative test method No. 69-1952 described on page 121 of the above reference. The tensile strength being measured on a Scott tester according to ASTM standards.

The yellowness index was calculated by the equation:

Yellowness index=70 1 Where R and R are reflectance values obtained on a recording spectrophotometegusing a magnesium carbonate block as a'reference standard, at the wavelengths of 455 millimicrons and 577 millimicrons, respectively.

The Washes under wrinkle recovery and chlorine retention were carried out by the test method 141953 described on page 123 of the above reference.

The sour washes were done in a Najort washer using 75 liters of water, 11 g. of a synthetic detergent, 0.01% available chlorine, 6-lb. load of cloth and a wash cycle of 20 minutes at 160 F. This was followed by a clear rinse of 10 minutes at 140 F., a second clear rinse of 5 minutes at 120 F., and a final sour rinse of 5 minutes at 120 F. with 4.5 g. of zinc silicofluoride in the rinse water. The cloth was tumble dried before the yellowness test.

Theresults of the test are shown in Table I Table I Percent composi- Wrinkle re- Chlorine re Yellowness tion of resin, covery total, tention, perindex solids basis degrees cent loss tensile strength Resin A Resin B Initial After 5 Initial After 5 Initial After 5 washes washes sour washes 0 227 232 0 20 1. 8 0. 5 75 25 223 213 2 1 2.1 1. b 50 50 221 224 0 3 2. 2 2.6 25 75 226 224 2 0 1. 7 4. 3 0 100 231 222 0 15 2. 1 5. 3 Untreated fabric- 134 158 0 0 1. 1 0. 6

This example shows that distilled uron resin has a low initial tensile strength loss due to chlorine retention, but that after 5 washes, i.e., washes at 212 F. with soap, it has a moderately high tensile strength loss. Also, this example shows that the tensile strength loss' due to rerially. increasing the yellowing due to chlorine retention. EXAMPLE 4 Resin A (distilled) =product of Example 2.

Resin A (crude)'=product of Example 1.

Pad baths were prepared containing 6.25% total resin solids of Resin A (distilled or crude) and Resin B, alone or in blends of 95/5, 85/15 and 75/25 solids ratios, with Resin A distilled and crude respectively. The pad baths also contained 12% of magnesium chloride based on the resin solids in the bath. Five percent resin solids on the weight of the fabric were applied to 80 x 80 cotton percale using an 80% Wet pick-up. The fabrics were dried at 225 F. for 1 minute and cured at 350 F. for 1.5 minutes.

The tests and washes were carried but as described in Example 3. The results of the tests are shown in Table II. The calculated values under percent loss tensile streng are calculated from the values found for 100% uron resin and 100% of the melamine resin.

Table II DISTILLED Chlorine retention, percent loss Percent composition tensile strength of resin, solids basis Initial After 5 washes Resin A Resin B Cale. Found Cale. Found 100 0 64 69 95 5 61 55 66 66 85 15 54 36 60 59 75 25 48 14 52 38 0 100 1 9 Untreated fabric 5 0 1 Calculated from the values for the 100% resins.

This example shows again that distilled uron resin has a negligible initial strength loss due to chlorine retention, with a high strength loss after 5 washes. However, crude uron resin shows a severe strength loss initially and after 5 washes.

With the addition of small amounts of the melamine resin to the distilled uron resin, the strength loss after 5 washes was reduced to a much greater extent than would be expected. (In the case of the 95/5 blend, the expected strength loss was 51%, while that round was only 16%.)

In the 'case of "the crude uron resin, unexpected improvements in the strength losses due to chlorine retention, both initially and after 5 washes, were obtained by adding the melamine resin. In this case, larger amounts of melamine resin were required than with the distilled uron resin. None of these blends were deficient in yellowness due to chlorine retention.

distilled or Resin A crude) with tris(methoxymethyl) melamine (MMM) are found in Table III below. These Table III V p 7 Chlorine retention, percent loss Percent composition tensile strength of resin, solids basis Initial After 5 washes Resin EU Resin B Cale Found Cale. Found Resin Resin B MMU 100 0 82 81 5 78 S3 79 84 85 15 70 78 71 88 75 25 62 72 63 S3 0 I 9 Resin A Resin distilled MMM Resin A Resin crude MMM 100 0 68 70 95 5 65 60 70 73 85 15 58 45 69 68 75 25 52 28 68 69 0 100 4 63 Untreated fabrie.- 5 0 1 Calculated from the values for the 100% resins.

Table III demonstrates that the improved results with respect to resistance to chlorine retention are peculiar to combinations of melamine and uron resins.

EXAMPLE 6 Resin A=product of Example 1.

Resin C=dimethylol ethylene urea plus equal molar amount of a substantially fully etherified fully methylolated melamine resin.

Pad baths were prepared containing 6.25% total resin solids of Resins A, B and C alone and as blends of Resin A with Resins B and C at 75/25 and 50/50 solids ratio, respectively. The pad baths also contain 12% of magnesium chloride based on the resin solids in the bath. Five percent resin solids on the weight of the fabric were applied to 80 x 80 cotton percale using an 80% wet pick-up. The fabrics were dried at 225 F. for one minute and cured at 350 F. for 1 /2 minutes.

The tests and washes, with the following exception, were carried out as described in Example 3.

In the oxalic acid and bleach, the fabric was stirred in a 2% aqueous oxalic acid solution at 100 F. for 10 minutes, rinsed in water, stirred in a 3% commercially available hypochlorite solution at F. for 20 minutes, and finally rinsed in water and dried. (This is a more severe test than the sour wash) The results of the test are shown in Table IV.

Table I V Percent composition or Chlorine retention, percent loss tensile Yellowness index resin, solids basis strength Initial After 5 washes Resin A Resin B Initial After 5 After oxalic sour washes acid and 02110. Found Cale. Found bleach Resin A Resin 0 Oalculated from the values for the 100% resins.

This example shows that the order of eifectiveness of the resins in reducing the strength losses due to chlorine retention was Resin B, followed by Resin C.

One of the principal advantages of the blends of this invention is that finishes obtained therewith have improved durability to sour washes, with respect to the durability obtained with either of the components alone.

EXAMPLE 7 Uron resins were applied in blends with various melamine resins to cotton percale so as to apply 5% total resin solids employing 12% magnesium chloride accelerator on the weight of resin solid. The treated fabrics were cured for 1 /2 minutes at 350 F. The various resins and their relative weight ratios in the blends employed are set forth in Table V hereinbelow. The sour washes referred to are described in Example 3.

Table V 1 4-0 Wrinkle recovery After 5 Initial, sour degree washes,

degree Untreated 147 162 5% resin solids, cured 1% at 850 F. with 12% (real) magnesium chloride on resin solids 1. Resin A distilled 243 220 RESIN A/RESIN B RESIN A/RESIN D 1 240 210 Resin D 243 213 16. Resin 0 249 212 17. /30 Resin A (crudc)/Resin B 252 235 18. 70/30 Resin A (distilled)/Resin B 245 223 1 Resin D=trimethoxyhexamethylol melamine (a partially alkylated substantially fully methylolated melamine).

Table V above clearly demonstrates that the blends of this invention are more durable to sour washes. Compare applications 1, and 14-16, with 2-13, 17, and 18.

The resinous composition of the present invention may be employed with other textile finishing resins, either thermosetting or thermoplastic, to improve the durability of such finishes or to modify the hand or other characteristics of the finished fabric. Thus, for example, the resinous product of this invention may be employed with other aminoplast textile finishing resins such as urea-formaldehyde resins, thiourea-formaldehyde resins, various cyclic ureas, as for example, 1,2-propylene ureaformaldehyde resins, 1,3-propylene urea-formaldehyde resins and their corresponding thioureas, guanamineformaldehyde resins and the alkylated derivatives of these materials. In addition to these, acetone-formaldehyde resins, epoxy resins such as diglycidyl ether, the diglycidyl ether of ethylene glycol, and other polyglycidyl ethers of polyhydric alcohols having an epoxy equivalency greater than 1, such as are disclosed in US. Patent 2,730,427 and 2,752,269, may also be employed. Among the thermoplastic resins which may be mentioned are honropolymers and copolymers of lower alkyl acrylates, such as methyl acrylates, ethyl acrylates, methyl methacrylates, butyl methacrylates or copolymers of these or their equivalents with styrenes, including ring and chain substituted styrenes, acrylonitrile, polyvinyl chloride, and the like. In addition, the resinous mixture of this invention may be employed with softeners, stiffeners, lubricants, dicyandiamide and other conventional treating bath components.

I claim:

1. A water soluble composition of matter comprising uron resin and an etherified methylol melamine in relative weight ratios per 100 parts by weight of resin solids of fromto 5 parts of uron resin and from 5 to 95 parts of melamine resin.

2. A composition according to claim 1 inwhich the uron resin is a distilled uron resin.

3. A composition according to claim 1 in which the uron resin is a crude uron resin.

4. A composition according to claim 1 in which the components are present in relative weight ratios of between about 65 to 95 parts of uron resin component to 35 to 5 parts of the melamine resin component.

5. A composition according to claim 1 in which the alkylated methylol melamine is an at least partially etherified and substantially fully methylolated melamine.

6. A process for finishing cellulose textile material whereby a wrinkle resistant finish resistant to the degradative effects of retained chlorine is obtained which comprises applying thereto a composition comprising a uron resin and an etherified methylol melamine in relative weight ratios per parts by weight of said resin solids of from 95 to 5 parts of uron resin and from 5 to 95 parts of melamine resin, and curing the resin finish by the action of an accelerator and heat.

7. A process according to claim 6 in which the mom resin is distilled uron resin.

8. A process according to claim 6 in which the uron resin is crude uron resin.

9. A process according to claim 6 in which the components are present in relative weight ratios of between about 65 to 95 parts of men resin component to about. 35 to 5 parts of melamine resin component.

10. A process according to claim 6 in which the etherified methylol melamine is an at least partially etherified substantially fully methylolated melamine.

ll. Cellulose containing textile material characterized by a wrinkle resistant finish, resistant to the degradative effects of retained chlorine, said finish comprising a composition containing a uron resin and an etherified methylol melamine in relative weight ratios per 100 parts by weight of said resin solids of from 95 to 5 parts of uron resin and from 5 to 95 parts of melamine resin cured with an accelerator and heat.

12. Cellulose containing textile material according to claim 11 in which the urea resin is distilled uron resin.

13. Cellulose containing textile material according to claim ll in which the uron resin is crude uron resin.

14. Cellulose containing textile material according to claim 13 in which the components are present in relative weight ratios of between about 65 to 95 parts of uron resin component to about 35 to 5 parts of melamine resin component. I

15. Cellulose containing textile material according to claim 11 in which the etherified methylolated melamine is an at least partially etherified substantially fully methylolated melamine.

l6. Cellulose containing textile material according to claim 11 which is cotton.

References Cited in the file of this patent UNITED STATES PATENTS 2,339,203 Stiegler et al. Ian. 11, 1944 2,373,135 Maxwell Apr. 10, 1945 2,749,257 Knup June 5, 1956 UNITED STATES PATENT OFFICE CERTIFICATEOF CORRECTION Philip B, Roth It is hereby certified that err ent requiring correction and that th corrected belo or appears in the above numbered pate said Letters Patent should read as Column 10, line 65, for -"alkylated" read etherified Signed and sealed this 20th day of August 1963,

(SEAL) Attest:

ERNEST W. SWIDER Attesting Officer DAVID L. LADD Commissioner of Patents

Claims

6. A PROCESS FOR FINISHING CELLULOSE TEXTILE MATERIAL WHEREBY A WRINKEL RESISTANT FINISH RESISTANT TO THE DEGRADATIVE EFFECTS OF RETAINED CHLORIDE IS OBTAINED WHICH COMPRISES APPLYING THERETO A COMPOSITION COMPRISING A URON RESIN AND AN ETHERIFIED METHYLOL MELAMINE IN RELATIVE WEIGHT RATIOS PER 100 PARTS BY WEIGHT OF SAID RESIN SOLIDS OF FROM 95 TO 5 PARTS OF URON RESIN AND FROM 5 TO 95 PARTS OF MELAMINE RESIN, AND CURING THE RESIN FINSIH BY THE ACTION OF AN ACCELERATOR AND HEAT.