CA1106271A - Method of preparing laminates and said laminates - Google Patents

Abstract

METHOD OF PREPARING LAMINATES
AND SAID LAMINATES

Abstract of the Disclosure A method of making a composition useful for making a laminate of a highly plasticized polyvinyl chlo-ride and a copolymer of 2-ethylhexyl methacrylate and acrylonitrile.

Description

11~6~t7~ .
.

This invention relates to a laminate having a base of highly plasticized polyvinyl chloride and a lamina of co-polymer of 60-30 parts of acrylonitrile and 40 to 70 parts

2-ethylhexyl methacrylate adhered thereto.
Copolymers of acrylate/vinyl nitrile are trans-parent and have useful properties of forming films by cast-ing, calendering or extrusion. Unfortunately~ these copoly-mers have poor adhesion to highly plasticized polyvinyl chloride, and thus laminates of these cannot be readily made. In general, the film laminates of this nature can only be made by incorporating organic isocyanate or polyiso-cyanate into polyvinyl chloride and/or the copolymer. These laminates are very desirable for outdoor usage where resis-tance to sunlight and weathering is required.
Canadian Patent 820,268 discloses how to produce a brittle laminate instead of a highly flexible laminate where the base is a polymer or copolymer of acrylic acid ester and the exposed lamina is non or low plasticized poly-vinyl chloride, preferably less than 20 percent. Also, the exposed polyvinyl chloride does not weather well.
An object of this invention is to provide films of the above copolymers that have good adhesive character-istics and thus permit laminates to be readily made with substrates such as highly plasticized polyvinyl chloride where the former serves as a top-dressing and dirt releas-ing agent. mis type of composite film has better service life than the single polyvinyl chloride film due to the protection afforded by the top or exposed coating in the prevention of plasticizer extraction, the screening effect 1 1~ 6 ~

for ultraviolet light, and the prevention of dirt pick--~p which tends to degrade the film prematurely.
An embodiment of this invention is a highly flexible, weather resistant laminate comprising a base of polyvinyl chloride containing 30 to 100 parts plasticizer per 100 parts polyvinyl chloride, having adhered to at least one f~ce thereo~ a layer of a copolymer of 60 to 30 parts of acrylonitrile with 40 to 70 parts of 2-ethylhexyl methacrylate.
The advantages of this invention can be readily obtained by preparing a copolymer of a 2-ethylhexyl metha-crylate/acrylonitrile and then using these copolymers alone to form a laminate with a highly plasticized polyvinyl chlo-ride, without the need to use adhesives in the substra~e polyvinyl chloride and/or copolymer or isocyanate.
The composite films were made up of these copoly-rners with highly plasticized polyvinyl chloride. Further variations on all these components are possible. Representa-tive examples of these useful and well known;plasticizers are dialkyl adipate esters, dialkyl azelates, some glycol di-benzoate esters, epoxy derivatives including epoxidized soy-bean oil, epoxidized tall oil and some epoxy resins, glycol-lates such as butyl phthalyl butyl glycollate, mellitates such as trialkyl trimellitates, phosphate esters including -triaryl, trialkyl and alkyl-aryl combinations, derivatives of phthalic acid with emphasis on dialkyl and alkyl benzyl phtha-lates, polyesters of various dibasic acids with glycols (e.g.
adipic, azelaic and phthalic acids with various glycols termi-nated with a monofunctional compound), some pentaerythritol derivatives, esters of citric acids and sebacic acids. These .

A

11~6Z71 plasticizers are added to the polyvinyl chloride in amounts of from 30 parts up to 100 parts, to obtain the highly fiex-ible, good weathering laminate of this invention. They include ratios of two monomers, various alkyl methacrylates where the alkyl group contains 1 to 30 carbon atoms and various vinyl nitriles such as methacrylonitrile and ethacrylonitrile. Al-o ~' ~1~6271 included is a composite film of highly plasticized polyvinyl chloride with a copolymer of 2 ethylhexyl acrylate and metha-crylonitrile. The film thickness of these copolymers and polyvinyl chloride which make up the composite film can be varied. The preferred ones are about two mils for these co-polymers and about 10 mils for polyvinyl chloride.
This object is achieved by polymerizing a mixture of about 40 to 70 parts 2-ethylhexyl methacrylate monomer and 30 to 60 parts of acrylonitrile monomer with a free radi-cal initiator such as the peroxide catalysts to yield a poly-mer soluble in tetrahydrofuran (THF) and readily castable from THF solution as a flexible film or otherwise shaped into the desired article. Usually the preferred copolymers of this invention can be made from the following precursors in amounts of about 40 to 70 phr (parts per hundred) of 2-ethyl-hexyl methacrylate (2-EHMA) and about 60 to 30 phr of acrylo-nitrile (AN). Where emulsion polymerization is used to make the polymer, various modifiers such as the aliphatic and aryl mercaptans or disulfides or even carbon tetrachloride, carbon tetrabromide, chloroform or iodoform can be used to advantage to control the polymer molecular weight and related physicals.
Also, the polymer properties can be modified to build in certain desirable attributes by including in the polymerization recipes crosslinkers such as triallyl cyanu-rate and ethylene glycol dimethacrylate. Small amounts of these crosslinkers, preferably 0.2 to 1.5 phr are desirable if the polymer is to be extended to form films.
The polymerization of the new copolymer of the 11~6271 present invention may be carried out in any conventional man-ner, although polymerization in an aqueous emulsion is pre-ferred. Alternately, polymerization may be carried ou-t in an aqueous suspension system, or in solution in a suitable well-known solvent for the monomer, such as methyl ethyl ketone and tetrahydrofuran.
Whatever method of polymerization is employed, any catalyst commonly employed may be used, including acti-nic radiation, peroxygen compounds such as hydrogen peroxide, cumene hydroperoxide and persulfates and percarbonates and azo or diazo compounds. These catalysts may be activated when used in combination with a reducing substance such as sodium and ferrous salts. Any of the usual emulsifying ; agents may be used, including ordinary soaps, such as the alkali metals of fatty acids including sodium oleate, and the detergents generally known as the sulfates and sulfo-nates, such as sodium lauryl sulfate and sodium isopropyl naphthalene sulfonate.
Polymerization may be carried out in the presence of air, but faster reactions are observed in the absence of oxygen at temperatures ranging from -30C. to 110C., al-though preferred temperatures range from about 5C. to about 80C.
A series of emulsion polymerizations of 2-EHMA/
AN were carried out in eight-ounce bottles as well as in five-gallon reactors. All the ingredients (0.05 phr potas-sium persulfate, 0.5 phr divinylbenzene, l.0 phr tertiary dodecyl mercaptan (t-DDM), 2.0 phr sodium tetradecyl sul-fate, lO0 phr total monomers in the ratio desired in the i;271 copolymer and 150 phr deionized water) were charged into eight-ounce bottles or five-gallon reactors and flushed well with nitrogen and -then reacted at 50C. to about 40 percent solids in 24 hours. Typically 60 parts 2-EHMA is used with 40 parts AN in the conventional polymerization recipe. The whole bottle was cooled to room temperature and three phr distilled water and 0.25 phr 30 percent H202 added and agi-tated for 20 minutes. Finally, this polymer was coagulated in 1.5 percent warm MgS04 solution (25-40C,), washed tho-roughly several times with distilled water and dried in an oven at 50C. for about one day. This copolymer consist-ed of 60/40 2-EHMA/AN respectively.
To those skilled in the art, one knows that various ingredients such as lubricants, stabilizers, pigments, toners, surfactants, ultra-violet absorbers, antioxidants, can be added to the film depending upon the intended use and na-ture thereof. In addition, the 2-EHMA/AN polymer can be extruded using proper equipment and conditions.
Polyvinyl chloride (PVC) resin was plasticized with 40 parts of plasticizers composed of 22.8 parts diiso-octyl phthalate, 7.4 parts N-octyl N-decyl phthalate, 5.7 parts tricresyl phosphate and 4.1 parts epoxy soya oil in a Hensche~ Mixer. Beside the plasticizers, the common recipe included in PVC was: 1.0 part 2-hydroxy-4-n-octoxy benzo-phenone, as a stabilizer, 2.6 parts Advastab~ BC lO~A (liquid barium cadmium zinc stabilizer for PVC), 1.5 parts Mark C
(alkyl aryl phosphate complex, a PVC stabilizer), 0.01 part of a dispersion of oil violet one percent, a color hiding agent) and 0.6 part triple pressed stearic acid (as a lubri-11~6271 cant). The PVC and the copolymer were dissolved in tetra-hydrofuran (THF) and 50/50 - THF/MEK respectively at 50 to 55C. using a low RPM air stirrer. Solution casting was done by draw-down operation using a Gardne~ fiber casting knife with micrometer and blade adjustments. Composite films (total thicknessr~ 12 mils) made up of PVC ( ~ lO mils) with a thin coating of copolymer (~J 2 mils) were made by a solution casting technique in the following way:
First, a single vinyl film was cast on a clean glass plate to give a film of approximately lO mils thick-ness af-ter drying in the hood overnight. Second, the co-polymer solution was cast on top of the dried single vinyl film to give a film of about 2 mils thickness. Third, this composite film was completely dried in the oven at 66C.
overnight. The polyvinyl chloride contains from 20 to 80 parts of plasticizer per hundred parts of polyvinyl chloride.
Alternately, the copolymers were compounded at 149C. with one part distearyl pentaerythrityl diphosphite, 1,5 parts Advastab BC 103A (liquid barium cadmium zinc sta-bilizer), l part 2-hydroxy-4-n-octoxy benzophenone and 2 parts polyethylene and then ground through one-fourth inch screen before they were coextruded with PVC (40 parts plas-ticizer) to make composite films. me following were coex-trusion conditions:
Pol~mer No. l Polymer No.2 Type: Copolymer PVC
State: Ground Pellets Extruder No. lExtruder No~2 L/D Ratio: 20/l; Dia: l-1/2"15/1; Dia: 1-1/2"

~ l'r~

~lC6271 Extruder No. 1 Extruder No. 2 . _ Mfg: NRM NRM
Screen Pack:20/40/120/40 mesh ~
Screw Type:Low compression PE Type >
5Adaptor and Die Composite Box:Research 2 layers Die Width:12"; Die type: flat Take-Off Equipment Describe: Casting unit Processing Conditions Extruder No. 1Extruder No. 2 Extr Throat, C.15.6 54.4 ~ -Extr Zone-l, C. 149 168 Extr Zone-2, C. 210 191 Extr Gate, C. 209 196 Extr Load, amp/k2.4 1.9 Barrel, psi 1200 1100 Melt Temp., C. 179 179 Extr, rpm 12 72 Polymers Copolymer PVC
Composite Box, C. 199 ~ -Die Adapt, C. 204 Die Zone-l, C. 201 Die Zone-2, C. 202 Cast Roll, C. 65.6 Chill Roll, C. R~To Wind-up, fpm 7-1/2 Total Gauge, mils 12 Film Width, ins. 11 Film length, ft. 50 Aging studies indicated that both cast and coex-truded composite films had excellent retention of tensile ` ;
strength and elongation. They exhibited no evidence of discoloration, surface crazing, surface cracking and pitting ~-after 7000 hours Xenon-arc Weatherometer, or 5000 hours Fadeometer, or 300 hours Accelerometer exposure. The test - `
results on the laminate are shown in Table 1.

- .

. . :
- -.

11(~6271 Table 1 PHYSICAL TEST DATA ON AGED FILMS
Laminated Film *
Modulus Tensile Ultimate Ph~sical Test at 100%~psi Strength,psi Elongation,%
Initial, unexposed1890** 2930 280 (1920)*** (2790) (220) 300 hrs. Accelerometer 1940 2850 300 Exposure(2270) (2360) (160) 5000 hrs. Fadeometer2500 2590 130 Exposure(2570) (2570) (120) 7000 hrs.Xenon-Arc2480 2950 280 Weatherometer exposure (-) (-) (-) *Laminated films were composed of about 10-12 mils PVC and about 2-4 mils copolymer (60/40-2-EHMA/AN). The copolymer film in the laminate faced the light for exposure.
**Data for solution cast laminated films.
***Numbers within parentheses are data for coextruded lami-nated films.
The physical test data in Table 1 indicates the laminated films prepared by either casting or coextrusion would be suitable for use in inflatable shelters, for exam-ple, green houses.

-. : ' 11~6i~71 * ~
* ~ ~
* ~o o o o ~ ~o $~a: ~ ~ L~
~~ ~ ~ C) P V~ o ~o O O o ~
~ ~ ,, o o o ~ P~ ~
O O rl ~ O +~

~i H * ~ ~¦ O O O O O
E-l * ~ J ~ V 11 U~ ~ ~1 u~ u~ ~ o r(~ V
O E~ 1:1 ~
~1 ~ . .~ ~ o ~ ~ O O ~
H ~ ~1 r l :~ ~ O O O O O ~1 0~ 0 ~ ~ a ~o .~ ~ ~ 0 0 ., ~ * ll +~ $ ' D~ S~ ~l~o ~ ~ ~ u~ ~ o ~ a ~' ~ ~ I o~ $.
~o ~ ~ o~ $
~ ~ ~o H N ~ ~ ~ `O P~

~ l ~ ~ ~ g o a) ~ ~
O ~ q O

H~ J 0 $ 1 a~ ~rl ~ H I V~ E~
~ ~OD ~ *
C~J ~ J 1~ * * * *

' - , . ' ' 11~6271 Table 2 shows physical properties of aged lamina-ted cast films composed of PVC containing from lO to 50 parts plasticizers and a copolymer (60/40 2-EHMA/AN). The laminates containing a plasticizer level of above 30 parts such as Sample Nos. 3, 4 and 5, had excellent retention of modulus at 100%, tensile strength and ultimate elongation after 5000 hours Xenon-arc Weatherometer exposure.
While certain representative embodiments and de-tails have been shown for the purpose of illustrating the invention, it will be apparent to those skilled in this art that various changes and modifications may be made therein without departing from the spirit or scope of the invention.

,

Claims (3)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A highly flexible, weather resistant laminate comprising a base of polyvinyl chloride containing 30 to 100 parts plasticizer per 100 parts polyvinyl chloride, hav-ing adhered to at least one face thereof a layer of a co-polymer of 60 to 30 parts of acrylonitrile with 40 to 70 parts of 2-ethylhexyl methacrylate.

2. The laminate of Claim 1 wherein the polyvinyl chloride is 5 to 30 mils thick and the copolymer is 1 to 10 mils thick.

3. The laminate of Claim 1 wherein the polyvinyl chloride contains 30 to 70 parts plasticizer per hundred parts polyvinyl chloride.