Classifications

• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
  • D21H19/00—Coated paper; Coating material
  • D21H19/36—Coatings with pigments
  • D21H19/44—Coatings with pigments characterised by the other ingredients, e.g. the binder or dispersing agent
  • D21H19/56—Macromolecular organic compounds or oligomers thereof obtained by reactions only involving carbon-to-carbon unsaturated bonds
  • D21H19/60—Polyalkenylalcohols; Polyalkenylethers; Polyalkenylesters

Definitions

• This invention relates to the use of aqueous emulsions in pigmented wallpaper ground coats.
• aqueous emulsions are based on vinyl alkanoate copolymers, usually vinyl acetate/ethylene copolymers.
• Pigmented wallpaper ground coats are applied on one side of a cellulosic wallpaper substrate. This side is then printed and will form the exposed surface when adhered to a wall.
• the wet rub resistance of the exposed surface is important because it allows the printed surface to be washed without eroding the decorative appearance.
• the invention provides for the use in a wallpaper ground coat of a copolymer emulsion latex having a solids contents of about 20% to about 70% by weight, preferably from about 40% to about 60%, wherein vinyl C1 to C13 alkanoate forms at least about 40% by weight of the monomer charge characterised in that
• vinyl acetate is the preferred vinyl alkanoate monomer because of its availability, cost and known reactivity
• other vinyl esters within the class defined are usable in particular vinyl formate, propionate, butyrate, isobutyrate, valerate, 2-ethyl hexanoate, isooctanoate, nonanoate, decanoate, pivalate and versatate.
• a preferred comonomer is ethylene but other ethylenic hydrocarbons, for example propylene, butylene and isobutene and higher alpha-olefins, are usable.
• the copolymer may contain minor monomer components added to provide specific benefits, examples are sodium vinyl sulphonate, acrylic acid, methacrylic acid, acrylamide, hydroxy functional acrylates, vinyl silanes and vinyl halides.
• a favoured comonomer is a polyethylenically unsaturated compound selected from triallyl cyanurate, triallyl isocyanurate, diallyl maleate, diallyl fumarate, divinyl benzene and diallyl phthalate.
• the epoxy silane used is preferably a gamma glycidoxy silane, having the formula x-Si(OR)3 whre X is an alkyl group containing a reactive expoxy moiety and R, which may be the same or different, is hydrogen, C1 to C4 alkyl radicals with not more than two of the radicals being hydrogen.
• X is an alkyl group containing a reactive expoxy moiety
• R which may be the same or different, is hydrogen, C1 to C4 alkyl radicals with not more than two of the radicals being hydrogen.
• Examples are gamma glycidoxy propyl trimethoxy silane and gamma glycidoxy propyl methoxy diethoxy silane.
• stabilising surfactant having an alkylene moeity examples include oleyl propanol amide sulphosuccinate obtained from Witco of USA under the trade name Emcol 8300 and the potassium salt of the sulphonation product of oleic acid obtainable from Lankro Chemcials of Manchester, England under the trade name Lankropol OPA.
• the coat composition was coated onto a wallpaper at a level of 25g/m2 and dried for 2 minutes at 120°C. It was then equilibrated overnight at 20°C and 65% RH. The coated wallpaper was then callendered twice at 50 to 55°C under a pressure of 200 lbs/sq in and then allowed to equilibrate overnight at 20°C and 65% RH before testing.
• Timperley testing machine fitted with a felt pad was used with a soft soap solution and set to operate at 120 ⁇ 10 strokes/minute. All groundcoats were tested to 150 rubs and visually graded for coating abrasion.
• the surfactant solution comprising a 37% aq solution of Emcol K8300 (87.7g), 30% aq solution of Aerosol A102 (61.5g) and ammonium persulphate (4.3g, initial charge) dissolved in deionised water (1038g) was prepared and charged to a 4 litre pressure vessel heated to 38°C. At 38°C the reactor was purged twice with nitrogen, once with ethylene and pressurised with ethylene to 800 psi with stirring. The temperature was adjusted to 75°C while 10% of the monomer phase was pumped to the reactor.
• reaction mass was held at 75°C for 30 minutes then the continuous additions of persulphate solution (5.3g in 300g of deionised water) and the remainder (90%) of the monomer phase were started.
• persulphate solution was added over 6.5 hours and the monomer phase over 6.0 hours.
• the pressure was maintained at 800 psi until the desired quantity of ethylene has been reacted, this was after 3.5 hours from start of continuous additions.
• reaction mass was held at 80°C for 30 minutes and the contents of the reactor then cooled to 40°C followed by pumping of finishing off stage (4.6g of each in 50g of deionised water) to the reactor, in separate streams, over 30 minutes.
• finishing off stage 4g of each in 50g of deionised water
• the contents of the reactor then cooled to 25°C and discharged to a degassing tank.
• Ammonia solution was used to adjust the pH of the emulsion latex to 8 then post-reacted with 1.0% epoxy silane while stirring.
• the emulsion had a solids content of 50%.
• Example 1-4 which contain acrylic acid as a functional comonomer, all show an improvement in scrub resistance on post-addition of epoxy silane. However results for example 5 show an improvement and here the acrylic acid is absent. It is however, regarded as essential that the polymerisation is performed in the presence of an effective amount of stabilising surfactant having a C14 to C20 alkylene moiety.
• a surfactant solution comprising a 37% aqueous solution of Emcol K8300 (15.7g), 31% aqueous solution of Aerosol A102 (11.0g) and ammonium persulphate (0.8g) dissolved in distilled water (180g) was charged to a 1 litre glass reactor, purged twice with nitrogen and heated to 75°C with stirring.
• a monomer mix comprising: vinyl acetate 200 g butyl acrylate 50 g acrylic acid 2.5 g diallyl maleate 0.5 g had been previously prepared and 10% was added to the reactor when the temperature reached 60 to 65°C. When the reactor temperature reached 75°C it was held at that temperature for 45 minutes.
• Ammonia solution was used to adjust the pH of the emulsion latex to 8 then post-reacted with the epoxy silane of Example I while stirring.
• the emulsion had a solids content of 50%.
• Example 6 The procedure of Example 6 was repeated but using a base monomer charge of: vinyl acetate 80% butyl acrylate 20% and a functional monomer charge: acrylic acid 0.5 pphm diallyl maleate 0.2 pphm sodium vinyl sulphonate 1.0 pphm
• Example 6 and 7 which contain acrylic acid as a functional comonomer, all show an improvement in scrub resistance on post-addition of epoxy silane, (Table 1). However, results for example 8 also shows an improvement and here the acrylic acid is absent. It is however regarded as essential that the polymerisation is performed in the presence of an effective amount of stabilising surfactant having a C14 to C20 alkylene moiety. This is demonstrated in example 9.

Landscapes

• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Emulsifying, Dispersing, Foam-Producing Or Wetting Agents (AREA)
• Addition Polymer Or Copolymer, Post-Treatments, Or Chemical Modifications (AREA)
• Paints Or Removers (AREA)
• Lubricants (AREA)
• Paper (AREA)
• Colloid Chemistry (AREA)

Priority Applications (1)

Applications Claiming Priority (2)

Publications (3)

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ID=10648457

Family Applications (1)

Country Status (7)

Cited By (2)

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• 1988
  • 1988-12-14 GB GB888829148A patent/GB8829148D0/en active Pending
• 1989
  • 1989-12-08 CA CA002005021A patent/CA2005021A1/en not_active Abandoned
  • 1989-12-12 AT AT89312937T patent/ATE102669T1/de not_active IP Right Cessation
  • 1989-12-12 EP EP89312937A patent/EP0375244B1/de not_active Expired - Lifetime
  • 1989-12-12 AU AU46180/89A patent/AU637588B2/en not_active Ceased
  • 1989-12-12 FI FI895917A patent/FI895917A7/fi not_active IP Right Cessation
  • 1989-12-12 DE DE68913687T patent/DE68913687T2/de not_active Expired - Fee Related

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