EP1001083A1 - Water retaining and optical brighteners activating polymeric composition, paper coating colours and coated paper - Google Patents

Abstract

Aqueous polymeric composition, stable in liquid form, which enables regulation of water retention, activation of whiteners and viscosity of paper sizes, comprises at least a polyvinylic alcohol (PVA) and at least a neutral or alkaline hydrosoluble polymer. Aqueous polymeric composition, stable in liquid form, which enables regulation of water retention, activation of whiteners and viscosity of paper sizes, comprises at least a polyvinylic alcohol (PVA) and at least a neutral or alkaline hydrosoluble polymer; said PVA having Ostwald viscosity less than 5 mPa.s corresponding to degree of polymerisation less than 600; and degree of hydrolysis = 70-100 mol.% measured from ester index corresponding to mol.% vinyl acetate groups = 30 - 0. Independent claims are also included for an aqueous suspension or slurry of mineral fillers containing the composition for use in paper sizes; and a sheet of paper coated with the suspension or slurry.

Description

The present invention relates to the technical sector of coating sheets of paper.

It is known that, in the techniques for coating sheets of paper, cardboard or the like, a coating composition is deposited on the surface or surfaces of the support which can contain one or more mineral fillers, one or more binders and various additives.

Among these additives, mention may be made of water retention agents, not to be confused with fine retention agents or fillers on the canvas.

The purpose of the coating is to improve certain physical and optical characteristics paper, such as its gloss, whiteness, opacity, capacity printing with ink, its 〈〈 smoothness 〉〉 and other properties of great importance commercial.

A paper coating composition generally consists of a filler which can be one or more pigments, one or more polymeric binders and various additives such as in particular a lubricant such as a calcium stearate, a wax, or a fatty acid ester, and optionally anti-foaming agents, and the like, well known of the skilled person.

After depositing on the support, the coating sauce has a natural tendency to transfer into the support, all or part of the water and of the water-soluble parts which it contains. It is necessary to control a migration too fast which would harm the characteristics physical and optical layer.

We therefore seek to retain water in the composition or coating sauce. Also, this water retention must be controlled to avoid an evolution in the rheology of the coating sauce not used and recycled in the coating process.

Natural agents or synthetics such as carboxymethylcellulose (CMC), starch, alcohols polyvinyl (PVA) or certain latex or highly polymer emulsions carboxylated or polycarboxylates, for example of the polyacrylate type. Such products are described for example in patent EP 0 509 878.

A particular class of retention agents is called alkali swellable polymers, and is described in the aforementioned EP patent, and as a prior art in US patent 4,780,500 which will be explained below.

It is naturally essential that the various additives do not degrade the others properties of the paper, such as its whiteness, its opacity, its mechanical resistance, etc.

The main important optical characteristics of paper are, among others, opacity, shine and whiteness, especially for printed media.

In order to improve the whiteness of a paper, it is known to add additives called Optiques optical brighteners 〉〉 which enhance the whiteness effect of the sheet.

These optical brighteners are generally and not limiting of the type comprising in their molecule the stilbene site substituted by diamines and groups sulfonic. These brighteners convert part of the invisible UV radiation in the radiation from the visible spectrum and generally in the range from blue to purple.

A nonlimiting example of a stilbene disulfonic acid derivative used as optical brightener is the product 〈〈 TINOPAL ™ (SPP Z or ABP Z or SK) 〉〉 marketed by the Ciba Company.

Another nonlimiting example of known optical brightener is the product 〈〈 BLANKOPHOR ™ (P or BPN) 〉〉 marketed by the Bayer Company.

Usually the effectiveness of these products depends on their activation. By 〈〈 activation 〉〉, we mean here the implementation of a co-product that will reveal and mainly to amplify the brightening effect.

However, we know that certain known water retention agents do not activate the brighteners. optical.

We also know that known products of polyvinyl alcohol type, or CMC limited use because of the high viscosities they develop in sauces in addition to their effectiveness on water retention.

The papermaker therefore finds himself in the presence of two properties which he is eminently desirable to strengthen, but which are mostly antagonistic.

For at least a decade, efforts have been made to optimize the effect of modern water retention, like thickening polymers, and that of brighteners activators optical and in particular PVA and other additives.

In patent EP 0 509 878, we recommend compositions 〈〈 which can be completely free of synthetic or natural thickeners 〉〉, page 2 line 52, which clearly shows the disadvantages of their use.

US Patent 4,780,500 describes water retention agents consisting essentially of acrylic acid monomer and secondarily of itaconic acid monomer, molecular weight from 100,000 to 800,000.

These two documents do not mention the problem posed by optical brighteners.

Patent GB 1 467 127 mentions the possible use of PVA as a binder in coating compositions, in the same way as starch, casein, etc. It mentions the possible presence of optical brighteners (page 2 line 10) but without posing the problem of their activation in relation to water retention.

US Patent 3,793,244 describes terpolymers of styrene, butadiene and acid itaconic water retaining and does not mention PVA.

Patent GB 1 271 282 describes a latex mixture, one of which has a high proportion of styrene. This latex mixture gives water retention but nowhere only the presence of PVA is indicated.

US Patent 3,687,884 describes a latex with vinyl acetate / acrylic acid backbone and styrene grafting.

US Patents 5,231,145 and US 5,240,771 teach that it is possible, by grafting, increase the amounts of PVA in the presence of copolymers provided that this copolymer is prepared by polymerizing it in the presence of PVA. They indicate other except that the simple mixing of this polymer with PVA does not make it possible to obtain a stable composition.

According to the invention, it has been discovered that, unlike patent teaching recent such as the above mentioned EP 0 509 878, it was possible to use certain PVAs specially selected, in combination with one or more retention agents of water, as a liquid aqueous composition optimizing both the retention function of water, that of activator of optical brighteners as well as that of viscosity regulator coating sauces, without the degradation of the water retention property that one could fear.

In addition, it should be noted that the liquid polymeric aqueous composition is stable, that is to say that it remains homogeneous for several days after storage without stirring at ambient temperature, this stability being an imperative condition of transport, use and marketing of the composition.

The invention also makes it possible to control the rheology of the coating sauces, that is to say to choose the viscosities of the medium according to the requirements of the application.

Without wishing to be bound by any theory, the Claimant considers that the selection criteria used for the choice of PWA according to the invention ensure the compatibility and stability with the retention agent.

• une viscosité inférieure à 5 mPa.s et de préférence comprise entre 2 mPa.s et 4 mPa.s mesurée selon la norme décrite ci-après, ce qui correspond à un degré de polymérisation inférieur à 600 et de préférence compris entre 250 et 500,
• et un pourcentage molaire d'hydrolyse compris entre 70 et 100 et de préférence entre 80 et 90 correspondant à un pourcentage molaire de motifs acétate de vinyle compris entre 30 et 0 et de préférence entre 20 et 10 mesuré à partir de l'indice d'ester (DIN 53401).

According to the invention, a precise selection of PVA is used, defined by:

• a viscosity less than 5 mPa.s and preferably between 2 mPa.s and 4 mPa.s measured according to the standard described below, which corresponds to a degree of polymerization less than 600 and preferably between 250 and 500 ,
• and a molar percentage of hydrolysis between 70 and 100 and preferably between 80 and 90 corresponding to a molar percentage of vinyl acetate units between 30 and 0 and preferably between 20 and 10 measured from the index of ester (DIN 53401).

According to a preferred embodiment, the polymer composition or composition polymer is characterized in that it contains a percentage of PVA greater than 20% by weight and preferably more than 50%.

The viscosity of the PVA is determined using Ostwald viscometer, ^No. 4080 apparatus from Prolabo with the capillary has a length of 100 mm and a reservoir with a capacity of 10 ml.

To do this, we start by preparing a 4% aqueous solution.

Thus, in a stoppered 60 ml bottle, a quantity of PVA weighed at 1 mg is introduced. close, corresponding to 2.105 g for a PVA at 1% humidity, 2.128 g for a PVA at 2% humidity, 2.151 g for a PVA at 3% humidity, or 2.174 g for a PVA at 4% humidity. Then 50 ml of distilled water, measured exactly with a pipette, are added.

It is plugged and stirred immediately using a heated magnetic stirrer.

The solution whose viscosity is to be determined must be free of materials insoluble materials capable of modifying the flow regime of the fluid in the capillary of the viscometer. It may therefore be necessary to filter or centrifuge the solution.

The 4% solution being thus prepared, the viscosity is measured using the aforementioned viscometer immersed in a thermostatically controlled bath at 20 ° C ± 0.05 ° C.

In the remainder of the present application and for reasons of simplification of writing, the viscosity determined according to this method will be noted viscosity of Ostwald and in particular the viscosities claimed.

The invention also relates to the stable liquid polymeric aqueous composition. optical brightener activator and water-retaining agent containing at least one PVA (alcohol polyvinyl) and at least one water-soluble polymer at neutral or alkaline pH, characterized in that the water-soluble polymer is a dispersion copolymer having more than 20% by weight (20% to 75%) of monomers containing acid groups and more particularly carboxylic.

The copolymer in dispersion can be chosen from copolymers of at least one acid-functional monomers such as acrylic and / or methacrylic acid, itaconic, citraconic, crotonic, fumaric, maleic, isocrotonic, mesaconic, sinapic, undecylenic, angelic and / or their respective anhydrides and / or hemiesters of diacids, acrylamido-methyl-propane-sulfonic acid, phosphates or acid sulfates of ethylene glycol acrylates and methacrylates, propylene glycol, butylene glycol, polyethylene glycol, polypropylene glycol and polybutylene glycol or other.

The monomer (s) without an acid group can be chosen without limitation among the derivatives of the aforementioned acids such as in particular the acrylates or methacrylates methyl, ethyl, butyl, 2-ethyl-hexyl, or among acrylonitrile, the methacrylonitrile, acrylamide, methacrylamide, n-methylolacrylamide, and among vinyl and / or styrenic monomers such as for example vinyl acetate, styrene, methylstyrene, diisobutylene, divinylbenzene, methylvinyl ether or also vinylcaprolactam or their mixtures.

They can also be chosen from oxyalkylated unsaturated monomers ethylenic terminated by a chain, linear or branched, such as linear groups or branched alkyl, aryl, alkylaryl, arylalkyl having from 1 to 50 carbon atoms and in particular the di-, tri- and tetrastyrylphenol groups, nonylphenols and others.

Finally, these monomers without acid group can optionally be chosen from monomers having at least two ethylenic unsaturations such as in particular, and without limitation, the group consisting of ethylene glycol dimethacrylate, trimethylolpropanetriacrylate, allyl acrylate, methylene-bis-acrylamide, methylene-bis-methacrylamide, tetrallyloxyethane, triallylcyanurate, ethers allylics obtained from polyols such as pentaerythritol, sorbitol, sucrose or other.

The invention also relates to the stable liquid polymeric aqueous composition. optical brightener activator and water-retaining agent containing at least one PVA (alcohol polyvinyl) and at least one water-soluble polymer at neutral or alkaline pH, characterized in that the water-soluble polymer is a water-soluble polyurethane.

The invention also relates to the stable liquid polymeric aqueous composition. optical brightener activator and water-retaining agent containing at least one PVA and at least a water-soluble polymer at neutral or alkaline pH, characterized in that the polymer water-soluble is a homopolymer or copolymer of a carboxylic acid used works in completely acidic form and in solution in water.

Finally, the invention relates to aqueous or slurry suspensions of mineral fillers containing the stable liquid polymeric aqueous composition according to the invention.

These mineral fillers are the mineral fillers such as, for example, those chosen among the natural calcium carbonates such as in particular chalk, calcite, marble or synthetic calcium carbonates, dolomites, kaolins, talc, titanium dioxide, satin white, mica, calcined clay, hydroxide aluminum, calcium sulfate or mixtures thereof.

Conventionally, the coating sauces are prepared by a person skilled in the art by mixture in water, aqueous suspensions of mineral charges, of one or more binders of natural or synthetic origin such as for example casein, starch, carboxymethylcellulose, polyvinyl alcohols or latexes of the styrene-butadiene type or styrene-acrylate or acrylic or vinyl latex or the like.

The coating sauces can also contain additives in a known manner usual such as rheology modifiers, organic fillers, anti-foaming agents, optical brighteners, biocidal agents, lubricants, hydroxides alkaline and others.

According to the invention, the paper coating sauces containing one or more fillers, one or more polymeric binders, water retentants, pigments, brighteners optical, and various other papermaking additives are characterized in that the retention of water, activation of optical brighteners and viscosities of coating sauces paper mill are regulated by a polymer composition, according to the invention, containing at least one polyvinyl alcohol (PVA) and at least one water-soluble polymer at pH neutral or alkaline.

Other characteristics and advantages of the invention will appear better on reading the description which will follow, and with reference to the examples below which cannot present any limiting character of the invention.

EXAMPLE I

This example concerns the comparison of the effectiveness of activators of optical brighteners known, such as CMC or certain PVA, with the effectiveness of activating compositions according to the invention.

Test # 1

• 100 parties, exprimées en matière sèche, d'une suspension aqueuse de carbonate de calcium commercialisée par la société Omya sous le nom 〈〈 HYDROCARB™ CC 〉〉
• 12 parties, exprimées en matière sèche, d'un latex styrène-acrylique commercialisé par la société BASF sous le nom 〈〈 ACRONAL™ S 360 D 〉〉
• 0,5 partie, exprimée en matière sèche, d'une solution de PVA commercialisé sous le nom de 〈〈 MOWIOL™ 3 / 83 〉〉 par la société Clariant
• 0,5 partie, exprimée en matière sèche, d'une carboxyméthylcellulose (CMC) commercialisée sous le nom 〈〈 FINNFIX™ 10 〉〉 par la société Metsä Serla
• 1 partie, exprimée en l'état, d'un azurant optique commercialisé par la société Bayer sous le nom 〈〈 BLANKOPHOR™ P 〉〉.

For this test which illustrates the prior art, the following coating sauce is prepared by mixing:

• 100 parts, expressed as dry matter, of an aqueous suspension of calcium carbonate marketed by the company Omya under the name 〈〈 HYDROCARB ™ CC 〉〉
• 12 parts, expressed as dry matter, of a styrene-acrylic latex marketed by the company BASF under the name 〈〈 ACRONAL ™ S 360 D 〉〉
• 0.5 part, expressed as dry matter, of a PVA solution marketed under the name of 〈〈 MOWIOL ™ 3/83 〉〉 by the company Clariant
• 0.5 part, expressed as dry matter, of a carboxymethylcellulose (CMC) marketed under the name 〈〈 FINNFIX ™ 10 〉〉 by the company Metsä Serla
• 1 part, expressed as is, of an optical brightener marketed by the company Bayer under the name 〈〈 BLANKOPHOR ™ P 〉〉.

The dry matter content is around 64% and the pH is around 8 to 9 per adjustment with aqueous sodium hydroxide solution.

Trial # 2

• 100 parties, exprimées en matière sèche, d'une suspension aqueuse de carbonate de calcium commercialisée par la société Omya sous le nom 〈〈 HYDROCARB™ CC 〉〉
• 12 parties, exprimées en matière sèche, d'un latex styrène-acrylique commercialisé par la société BASF sous le nom 〈〈 ACRONAL™ S 360 D 〉〉
• 0,5 partie, exprimée en matière séche, d'une solution de PVA commercialisé sous le nom de 〈〈 MOWIOL™ 6 / 98 〉〉 par la société Clariant
• 0,5 partie, exprimée en matière sèche, d'une carboxyméthylcellulose (CMC) commercialisée sous le nom 〈〈 FINNFIX™ 10 〉〉 par la société Metsä Serla.
• 1 partie, exprimée en l'état, d'un azurant optique commercialisé par la société Bayer sous le nom 〈〈 BLANKOPHOR™ P 〉〉.

For this test which illustrates the prior art, the following coating sauce is prepared by mixing:

• 100 parts, expressed as dry matter, of an aqueous suspension of calcium carbonate marketed by the company Omya under the name 〈〈 HYDROCARB ™ CC 〉〉
• 12 parts, expressed as dry matter, of a styrene-acrylic latex marketed by the company BASF under the name 〈〈 ACRONAL ™ S 360 D 〉〉
• 0.5 part, expressed as dry matter, of a PVA solution sold under the name of 〈〈 MOWIOL ™ 6/98 〉〉 by the company Clariant
• 0.5 part, expressed as dry matter, of a carboxymethylcellulose (CMC) sold under the name 〈〈 FINNFIX ™ 10 〉〉 by the company Metsä Serla.
• 1 part, expressed as is, of an optical brightener marketed by the company Bayer under the name 〈〈 BLANKOPHOR ™ P 〉〉.

The dry matter content is around 64% and the pH is around 8 to 9 per adjustment with aqueous sodium hydroxide solution.

Test # 3

• 100 parties, exprimées en matière sèche, d'une suspension aqueuse de carbonate de calcium commercialisée par la société Omya sous le nom 〈〈 HYDROCARB™ CC 〉〉
• 12 parties, exprimées en matière sèche, d'un latex styrène-acrylique commercialisé par la société BASF sous le nom 〈〈 ACRONAL™ S 360 D 〉〉
• 1 partie, exprimée en matière sèche, d'une carboxyméthylcellulose (CMC) commercialisée sous le nom 〈〈 FINNFIX ™ 10 〉〉 par la société Metsä Serla
• 1 partie, exprimée en l'état, d'un azurant optique commercialisé par la société Bayer sous le nom 〈〈 BLANKOPHOR™ P 〉〉.

For this test which illustrates the prior art, the following coating sauce is prepared by mixing:

• 100 parts, expressed as dry matter, of an aqueous suspension of calcium carbonate marketed by the company Omya under the name 〈〈 HYDROCARB ™ CC 〉〉
• 12 parts, expressed as dry matter, of a styrene-acrylic latex marketed by the company BASF under the name 〈〈 ACRONAL ™ S 360 D 〉〉
• 1 part, expressed as dry matter, of a carboxymethylcellulose (CMC) sold under the name 〈〈 FINNFIX ™ 10 〉〉 by the company Metsä Serla
• 1 part, expressed as is, of an optical brightener marketed by the company Bayer under the name 〈〈 BLANKOPHOR ™ P 〉〉.

The dry matter content is around 64% and the pH is around 8 to 9 per adjustment with aqueous sodium hydroxide solution.

Trial # 4

• 100 parties, exprimées en matière sèche, d'une suspension aqueuse de carbonate de calcium commercialisée par la société Omya sous le nom 〈〈 HYDROCARB™ CC 〉〉
• 12 parties, exprimées en matière sèche, d'un latex styrène-acrylique commercialisé par la société BASF sous le nom 〈〈 ACRONAL™ S 360 D 〉〉
• 1 partie, exprimée en matière séche, d'une solution de PVA commercialisée sous le nom de 〈〈 MOWIOL™ 3 / 83 〉〉 par la société Clariant.
• 1 partie, exprimée en l'état, d'un azurant optique commercialisé par la société Bayer sous le nom 〈〈 BLANKOPHOR™ P 〉〉

For this test which illustrates the prior art, the following coating sauce is prepared by mixing:

• 100 parts, expressed as dry matter, of an aqueous suspension of calcium carbonate marketed by the company Omya under the name 〈〈 HYDROCARB ™ CC 〉〉
• 12 parts, expressed as dry matter, of a styrene-acrylic latex marketed by the company BASF under the name 〈〈 ACRONAL ™ S 360 D 〉〉
• 1 part, expressed as dry matter, of a PVA solution marketed under the name of 〈〈 MOWIOL ™ 3/83 〉〉 by the company Clariant.
• 1 part, expressed as is, of an optical brightener marketed by the company Bayer under the name 〈〈 BLANKOPHOR ™ P 〉〉

The dry matter content is around 64% and the pH is around 8 to 9 per adjustment with aqueous sodium hydroxide solution.

Test # 5

• 100 parties, exprimées en matière sèche, d'une suspension aqueuse de carbonate de calcium commercialisée par la société Omya sous le nom 〈〈 HYDROCARB™ CC 〉〉
• 12 parties, exprimées en matière sèche, d'un latex styrène-acrylique commercialisé par la société BASF sous le nom 〈〈 ACRONAL™ S 360 D 〉〉
• 1 partie, exprimée en matière séche, d'un copolymère en dispersion de l'art antérieur constitué de 37 % en poids d'acide méthacrylique et 63% en poids d'acrylate d'éthyle et dénommé produit n°1
• 1 partie, exprimée en l'état, d'un azurant optique commercialisé par la société Bayer sous le nom 〈〈 BLANKOPHOR™ P 〉〉

For this test which illustrates the prior art, the following coating sauce is prepared by mixing:

• 100 parts, expressed as dry matter, of an aqueous suspension of calcium carbonate marketed by the company Omya under the name 〈〈 HYDROCARB ™ CC 〉〉
• 12 parts, expressed as dry matter, of a styrene-acrylic latex marketed by the company BASF under the name 〈〈 ACRONAL ™ S 360 D 〉〉
• 1 part, expressed as dry matter, of a copolymer in dispersion of the prior art consisting of 37% by weight of methacrylic acid and 63% by weight of ethyl acrylate and called product n ° 1
• 1 part, expressed as is, of an optical brightener marketed by the company Bayer under the name 〈〈 BLANKOPHOR ™ P 〉〉

The dry matter content is around 64% and the pH is around 8 to 9 per adjustment with aqueous sodium hydroxide solution.

• 100 parties, exprimées en matière sèche, d'une suspension aqueuse de carbonate de calcium commercialisée par la société Omya sous le nom 〈〈 HYDROCARB™ CC 〉〉
• 12 parties, exprimées en matière sèche, d'un latex styrène-acrylique commercialisé par la société BASF sous le nom 〈〈 ACRONAL™ S 360 D 〉〉
• 1 partie, exprimée en matière sèche, d'une composition polymérique selon l'invention
• 1 partie, exprimée en l'état, d'un azurant optique commercialisé par la société Bayer sous le nom 〈〈 BLANKOPHOR™ P 〉〉

For the tests according to the invention (tests n ° 6 to 13), the coating sauces according to the invention are prepared by mixing:

• 100 parts, expressed as dry matter, of an aqueous suspension of calcium carbonate marketed by the company Omya under the name 〈〈 HYDROCARB ™ CC 〉〉
• 12 parts, expressed as dry matter, of a styrene-acrylic latex marketed by the company BASF under the name 〈〈 ACRONAL ™ S 360 D 〉〉
• 1 part, expressed as dry matter, of a polymer composition according to the invention
• 1 part, expressed as is, of an optical brightener marketed by the company Bayer under the name 〈〈 BLANKOPHOR ™ P 〉〉

The dry matter content is around 64% and the pH is around 8 to 9 per adjustment with aqueous sodium hydroxide solution.

The polymeric composition of optical brightener activator and water-retaining, according to the invention is:

Test # 6

A polymer composition, according to the invention, consisting of 70% by weight of a PVA of Ostwald viscosity equal to 3.5 mPa.s and molar percentage of hydrolysis equal to 87.5 measured from the ester index (DIN 53401) and 30% by weight of a copolymer composed of 39% by weight of methacrylic acid, 55% by weight of acrylate ethyl and 6% by weight of a precondensate of ethylene glycol methacrylate and toluene diisocyanate condensed on nonylphenol with 50 units of ethylene oxide.

The product according to the invention is named, in the rest of the application, product n ° 2.

Test # 7

A polymer composition, according to the invention, consisting of 70% by weight of a PVA Ostwald viscosity equal to 3.5 mPa.s and molar percentage of hydrolysis equal to 87.5 measured from the ester index (DIN 53401) and 30% by weight of a copolymer composed of 37% by weight of methacrylic acid, 54% by weight of acrylate ethyl and 9% by weight of a precondensate of ethylene glycol methacrylate and toluene diisocyanate condensed on nonylphenol with 50 units of ethylene oxide.

The product according to the invention is named, in the rest of the application, product n ° 3.

Trial # 8

A polymer composition, according to the invention, consisting of 80% by weight of a PVA Ostwald viscosity equal to 3.5 mPa.s and molar percentage of hydrolysis equal to 87.5 measured from the ester index (DIN 53401) and 20% by weight of a copolymer composed of 42% by weight of methacrylic acid, 54.1% by weight of ethyl acrylate, 0.8% by weight of n-methylol acrylamide, of 1.6% of ethylene glycol dimethacrylate and 1.5% acrylamide.

The product according to the invention is named, in the rest of the application, product n ° 4.

Test # 9

A polymer composition, according to the invention, consisting of 70% by weight of a PVA Ostwald viscosity equal to 3.5 mPa.s and molar percentage of hydrolysis equal to 87.5 measured from the ester index (DIN 53401) and 30% by weight of a copolymer composed of 37% by weight of methacrylic acid, 54% by weight of acrylate ethyl and 9% by weight of tristyrylphenol methacrylate with 25 oxide units ethylene.

The product according to the invention is named, in the rest of the application, product n ° 5.

Test # 10

A polymer composition, according to the invention, consisting of 70% by weight of a PVA Ostwald viscosity equal to 3.5 mPa.s and molar percentage of hydrolysis equal to 87.5 measured from the ester index (DIN 53401) and 30% by weight of a copolymer composed of 37% by weight of methacrylic acid and 63% by weight ethyl acrylate.

The product according to the invention is named, in the rest of the application, product n ° 6.

Trial # 11

A polymer composition, according to the invention, consisting of 70% by weight of a PVA Ostwald viscosity equal to 3.5 mPa.s and molar percentage of hydrolysis equal to 87.5 measured from the ester index (DIN 53401) and 30% by weight of a copolymer composed of 44% by weight of methacrylic acid, 15% by weight of acrylate butyl and 41% by weight of styrene.

The product according to the invention is named, in the rest of the application, product n ° 7.

Test # 12

A polymer composition, according to the invention, consisting of 70% by weight of a PVA Ostwald viscosity equal to 3.5 mPa.s and molar percentage of hydrolysis equal to 87.5 measured from the ester index (DIN 53401) and 30% by weight of a polyurethane polycondensate of lauric alcohol, diisocyanate and polyalkylene glycol.

The product according to the invention is named, in the rest of the application, product n ° 8.

Test # 13

A polymer composition, according to the invention, consisting of 70% by weight of a PVA Ostwald viscosity equal to 3.5 mPa.s and molar percentage of hydrolysis equal to 87.5 measured from the ester index (DIN 53401) and 30% by weight of a polyurethane, polycondensate of octanol, diisocyanate and polyalkylene glycol.

The product according to the invention is named, in the rest of the application, product n ° 9.

Trial # 14

A polymer composition, according to the invention, consisting of 70% by weight of a PVA Ostwald viscosity equal to 3.5 mPa.s and molar percentage of hydrolysis equal to 87.5 measured from the ester index (DIN 53401) and 30% by weight of a homopolymer of acrylic acid in solution in fully acidic form.

The product according to the invention is named, in the rest of the application, product n ° 10.

Trial # 15

A polymer composition, according to the invention, consisting of 70% by weight of a PVA Ostwald viscosity equal to 3.5 mPa.s and molar percentage of hydrolysis equal to 87.5 measured from the ester index (DIN 53401), from 15% by weight of a copolymer composed of 37% by weight of methacrylic acid and 63% by weight of acrylate ethyl, and 15% by weight of another copolymer composed of 44% by weight of acid methacrylic, 15% by weight of butyl acrylate and 41% by weight of styrene.

The product according to the invention is named, in the rest of the application, product n ° 11.

Trial # 16

A calcium carbonate slurry 〈〈 HYDROCARB ™ CC 〉〉 from the company Omya containing the polymer composition consisting of 70% by weight of a PVA of Ostwald viscosity equal to 3.5 mPa.s and molar percentage of hydrolysis equal to 87.5 measured from the ester index (DIN 53401) and 30% by weight of a copolymer composed of 37% by weight of methacrylic acid and 63% by weight of acrylate ethyl.

The product according to the invention is named, in the rest of the application, product n ° 12.

All the coating sauces thus prepared are subjected to a measurement test of the water retention with the method described below.

The coating sauce is subjected to a pressure of 100 psi (7 bars) in a cylinder standardized, equipped with a filter paper type surface capable of letting water pass.

• le volume d'eau collecté après 20 minutes (évalué en ml).

A value is measured:

• the volume of water collected after 20 minutes (evaluated in ml).

The lower the volume of water collected after 20 minutes, the better the retention of water.

To do this, use a filter press 〈〈 API Fluid Loss Measurement 〉〉 (figure 1/1) of the Baroid Company which essentially consists of a stirrup (1) fitted with a screw clamping (2) allowing the blocking of the three parts of the filter body (3).

• d'une embase (4) percée d'un trou et dotée d'un ajutage par lequel s'écoule le filtrat. Cette embase (4) supporte un tamis métallique (5) de 60 à 80 mesh sur lequel est placé le papier filtre (6) de 90 mm de diamètre (Whatman™ n° 50) dont l'équivalent est le type DURIEUX BLEU™ n^o 3
• d'un cylindre de diamètre intérieur de 76,2 mm et de hauteur de 128 mm.
• d'un couvercle (7) muni d'une arrivée de gaz comprimé, dont l'étanchéité avec le cylindre est assurée à l'aide d'un joint plat (8), du même type que ceux (9) placés sur l'embase (4).

This body (3) consists of:

• a base (4) pierced with a hole and provided with a nozzle through which the filtrate flows. This base (4) supports a metal screen (5) of 60 to 80 mesh on which is placed the filter paper (6) 90 mm in diameter (Whatman ™ n ° 50) whose equivalent is the type DURIEUX BLEU ™ n ^o 3
• a cylinder with an internal diameter of 76.2 mm and a height of 128 mm.
• a cover (7) provided with a compressed gas inlet, the sealing of which with the cylinder is ensured by means of a flat seal (8), of the same type as those (9) placed on the base (4).

• le joint (9) sur l'embase (4),
• le tamis (5) sur le joint (9),
• le papier filtre (6) sur le tamis (5),
• le second joint (10) sur le papier filtre (6),
• emboíter le cylindre sur l'embase (4) et verrouiller le système à baillonnette.

To use the filter press, install in order:

• the seal (9) on the base (4),
• the screen (5) on the seal (9),
• the filter paper (6) on the screen (5),
• the second seal (10) on the filter paper (6),
• fit the cylinder on the base (4) and lock the bail system.

Fill with sauce (about 480 g, up to about 3 cm from the top of the cylinder).

Place the cover (7) on the cylinder, inserting a seal (8).

Place the assembly in the bracket (1), and secure with the clamping screw (2).

Place a graduated cylinder (12) under the nozzle.

Apply a pressure of 7 bars and simultaneously start the stopwatch.

We then note after 20 mm, the volume of fluid collected in the test piece (12) (expressed in ml). The accuracy of the result obtained is ± 0.2 ml.

Direct measurement of the 100% UV whiteness of coated papers with sauces coating, according to the TAPPI T 452 ISO 2470 standard used in this example, is set works in the following way.

For each test, there is a sheet of wood-free paper of dimension 21 x 29.7 cm with a specific weight of 41 g / m ² which is coated with the coating sauce to be tested using a laboratory coater with exchangeable rolling blades sold under the reference Mod. KCC 202 (™) by Erichsen.

Each sheet of paper thus coated at 14-15 g / m ² and then dried in a non-ventilated oven sold by the company JOUAN, for 5 minutes at 50 ° C. is then subjected to light radiation of wavelength equal to 457 nm. using an Elrepho 3000 spectrophotometer from 〈〈 Data Color 〉〉 (™) to determine whiteness.

The accuracy of the whiteness result obtained is ± 1.

The Brookfield viscosity of the coating sauces was also measured at 10 and 100 rpm at 25 ° C, using a Brookfield viscometer type DV-1 equipped with the mobile adequate.

The results are collated in Tables Ia. and Ib. below.

Reading Tables Ia. and Ib. shows that only the coatings sauces according to the invention have both good whiteness and good retention and this by implementation of a single product according to the invention instead of two as in the art prior. Indeed test n ° 5 of the prior art, which uses only one product, has good water retention but poor whiteness.

In addition, reading these Tables Ia. and Ib., and in particular the comparison of tests n ° 1 and n ° 12, also makes it possible to see that the coating sauces according to the invention allow you to choose the desired Brookfield viscosity while retaining retention of water and the activation of optical brighteners.

EXAMPLE II

In a second group of tests (n ° 17 to n ° 32), we repeated, with the same mode procedure and the same material, the operations and measurements of Example I but in replacing the 100 dry parts of calcium carbonate of Example I with 70 parts by dry weight of an aqueous suspension of calcium carbonate Hydrocarb ™ 90ME of Omya and 30 parts by dry weight of kaolin Hydragloss ™ 90 from the company Huber.

The different tests are:

Trial # 17

• 100 parties, exprimées en matière sèche, composées de 70 parties en poids sec d'une suspension aqueuse de carbonate de calcium Hydrocarb™ 90ME de la société Omya et 30 parties en poids sec de kaolin Hydragloss™ 90 de la société Huber.
• 12 parties, exprimées en matière sèche, d'un latex styrène-acrylique commercialisé par la société BASF sous le nom 〈〈 ACRONAL™ S 360 D 〉〉
• 0,5 partie, exprimée en matière séche, d'une solution de PVA commercialisé sous le nom de 〈〈 MOWIOL™ 3 / 83 〉〉 par la société Clariant
• 0,5 partie, exprimée en matière sèche, d'une carboxyméthylcellulose (CMC) commercialisée sous le nom 〈〈 FINNFIX™ 10 〉〉 par la société Metsä Serla.
• 1 partie, exprimée en l'état, d'un azurant optique commercialisé par la société Bayer sous le nom 〈〈 BLANKOPHOR™ P 〉〉

This test illustrates the prior art and uses the following coating sauce by mixing:

• 100 parts, expressed as dry matter, composed of 70 parts by dry weight of an aqueous suspension of calcium carbonate Hydrocarb ™ 90ME from the company Omya and 30 parts by dry weight of kaolin Hydragloss ™ 90 from the company Huber.
• 12 parts, expressed as dry matter, of a styrene-acrylic latex marketed by the company BASF under the name 〈〈 ACRONAL ™ S 360 D 〉〉
• 0.5 part, expressed as dry matter, of a PVA solution marketed under the name of 〈〈 MOWIOL ™ 3/83 〉〉 by the company Clariant
• 0.5 part, expressed as dry matter, of a carboxymethylcellulose (CMC) sold under the name 〈〈 FINNFIX ™ 10 〉〉 by the company Metsä Serla.
• 1 part, expressed as is, of an optical brightener marketed by the company Bayer under the name 〈〈 BLANKOPHOR ™ P 〉〉

The dry matter content is around 64% and the pH is around 8 to 9 per adjustment with aqueous sodium hydroxide solution.

Trial # 18

• 100 parties, exprimées en matière sèche, composées de 70 parties en poids sec d'une suspension aqueuse de carbonate de calcium Hydrocarb™ 90ME de la société Omya et 30 parties en poids sec de kaolin Hydragloss™ 90 de la société Huber.
• 12 parties, exprimées en matière sèche, d'un latex styrène-acrylique commercialisé par la société BASF sous le nom 〈〈 ACRONAL™ S 360 D 〉〉
• 0,5 partie, exprimée en matière sèche, d'une solution de PVA commercialisé sous le nom de 〈〈 MOWIOL™ 6 / 98 〉〉 par la société Clariant.
• 0,5 partie, exprimée en matière sèche, d'une carboxyméthylcellulose (CMC) commercialisée sous le nom 〈〈 FINNFIX™ 10 〉〉 par la société Metsä Serla.
• 1 partie, exprimée en l'état, d'un azurant optique commercialisé par la société Bayer sous le nom 〈〈 BLANKOPHOR™ P 〉〉.

This test illustrates the prior art and uses the following coating sauce by mixing:

• 100 parts, expressed as dry matter, composed of 70 parts by dry weight of an aqueous suspension of calcium carbonate Hydrocarb ™ 90ME from the company Omya and 30 parts by dry weight of kaolin Hydragloss ™ 90 from the company Huber.
• 12 parts, expressed as dry matter, of a styrene-acrylic latex marketed by the company BASF under the name 〈〈 ACRONAL ™ S 360 D 〉〉
• 0.5 part, expressed as dry matter, of a PVA solution sold under the name of 〈〈 MOWIOL ™ 6/98 〉〉 by the company Clariant.
• 0.5 part, expressed as dry matter, of a carboxymethylcellulose (CMC) sold under the name 〈〈 FINNFIX ™ 10 〉〉 by the company Metsä Serla.
• 1 part, expressed as is, of an optical brightener marketed by the company Bayer under the name 〈〈 BLANKOPHOR ™ P 〉〉.

The dry matter content is around 64% and the pH is around 8 to 9 per adjustment with aqueous sodium hydroxide solution.

Test n ° 19

• 100 parties, exprimées en matière sèche, composées de 70 parties en poids sec d'une suspension aqueuse de carbonate de calcium Hydrocarb™ 90ME de la société Omya et 30 parties en poids sec de kaolin Hydragloss™ 90 de la société Huber.
• 12 parties, exprimées en matière sèche, d'un latex styrène-acrylique commercialisé par la société BASF sous le nom 〈〈 ACRONAL™ S 360 D 〉〉
• 1 partie, exprimée en matière sèche, d'une carboxyméthylcellulose (CMC) commercialisée sous le nom 〈〈 FINNFIX™ 10 〉〉 par la société Metsä Serla.
• 1 partie, exprimée en l'état, d'un azurant optique commercialisé par la société Bayer sous le nom 〈〈 BLANKOPHOR™ P 〉〉

This test illustrates the prior art and uses the following coating sauce by mixing:

• 100 parts, expressed as dry matter, composed of 70 parts by dry weight of an aqueous suspension of calcium carbonate Hydrocarb ™ 90ME from the company Omya and 30 parts by dry weight of kaolin Hydragloss ™ 90 from the company Huber.
• 12 parts, expressed as dry matter, of a styrene-acrylic latex marketed by the company BASF under the name 〈〈 ACRONAL ™ S 360 D 〉〉
• 1 part, expressed as dry matter, of a carboxymethylcellulose (CMC) sold under the name 〈〈 FINNFIX ™ 10 〉〉 by the company Metsä Serla.
• 1 part, expressed as is, of an optical brightener marketed by the company Bayer under the name 〈〈 BLANKOPHOR ™ P 〉〉

The dry matter content is around 64% and the pH is around 8 to 9 per adjustment with aqueous sodium hydroxide solution.

Trial # 20

• 100 parties, exprimées en matière sèche, composées de 70 parties en poids sec d'une suspension aqueuse de carbonate de calcium Hydrocarb™ 90ME de la société Omya et 30 parties en poids sec de kaolin Hydragloss™ 90 de la société Huber.
• 12 parties, exprimées en matière sèche, d'un latex styrène-acrylique commercialisé par la société BASF sous le nom 〈〈 ACRONAL™ S 360 D 〉〉
• 1 partie, exprimée en matière sèche, d'une solution de PVA commercialisé sous le nom de 〈〈 MOWIOL™ 3 / 83 〉〉 par la société Clariant.
• 1 partie, exprimée en l'état, d'un azurant optique commercialisé par la société Bayer sous le nom 〈〈 BLANKOPHOR™ P 〉〉

This test illustrates the prior art and uses the following coating sauce by mixing:

• 100 parts, expressed as dry matter, composed of 70 parts by dry weight of an aqueous suspension of calcium carbonate Hydrocarb ™ 90ME from the company Omya and 30 parts by dry weight of kaolin Hydragloss ™ 90 from the company Huber.
• 12 parts, expressed as dry matter, of a styrene-acrylic latex marketed by the company BASF under the name 〈〈 ACRONAL ™ S 360 D 〉〉
• 1 part, expressed as dry matter, of a PVA solution sold under the name of 〈〈 MOWIOL ™ 3/83 〉〉 by the company Clariant.
• 1 part, expressed as is, of an optical brightener marketed by the company Bayer under the name 〈〈 BLANKOPHOR ™ P 〉〉

The dry matter content is around 64% and the pH is around 8 to 9 per adjustment with aqueous sodium hydroxide solution.

Trial # 21

• 100 parties, exprimées en matière sèche, composées de 70 parties en poids sec d'une suspension aqueuse de carbonate de calcium Hydrocarb™ 90ME de la société Omya et 30 parties en poids sec de kaolin Hydragloss™ 90 de la société Huber.
• 12 parties, exprimées en matière sèche, d'un latex styrène-acrylique commercialisé par la société BASF sous le nom 〈〈 ACRONAL™ S 360 D 〉〉
• 1 partie, exprimée en matière séche, d'un copolymère en dispersion de l'art antérieur constitué de 37 % en poids d'acide méthacrylique et 63 % en poids d'acrylate d'éthyle et dénommé produit n°1
• 1 partie, exprimée en l'état, d'un azurant optique commercialisé par la société Bayer sous le nom 〈〈 BLANKOPHOR™ P 〉〉.

This test illustrates the prior art and uses the following coating sauce by mixing:

• 100 parts, expressed as dry matter, composed of 70 parts by dry weight of an aqueous suspension of calcium carbonate Hydrocarb ™ 90ME from the company Omya and 30 parts by dry weight of kaolin Hydragloss ™ 90 from the company Huber.
• 12 parts, expressed as dry matter, of a styrene-acrylic latex marketed by the company BASF under the name 〈〈 ACRONAL ™ S 360 D 〉〉
• 1 part, expressed as dry matter, of a copolymer in dispersion of the prior art consisting of 37% by weight of methacrylic acid and 63% by weight of ethyl acrylate and called product n ° 1
• 1 part, expressed as is, of an optical brightener marketed by the company Bayer under the name 〈〈 BLANKOPHOR ™ P 〉〉.

The dry matter content is around 64% and the pH is around 8 to 9 per adjustment with aqueous sodium hydroxide solution.

Trial # 22

• 100 parties, exprimées en matière sèche, composées de 70 parties en poids sec d'une suspension aqueuse de carbonate de calcium Hydrocarb™ 90ME de la société Omya et 30 parties en poids sec de kaolin Hydragloss™ 90 de la société Huber.
• 12 parties, exprimées en matière sèche, d'un latex styrène-acrylique commercialisé par la société BASF sous le nom 〈〈 ACRONAL™ S 360 D 〉〉
• 1 partie, exprimée en matière sèche, d'une composition polymérique selon l'invention, dénommé produit n° 13
• 1 partie, exprimée en l'état, d'un azurant optique commercialisé par la société Bayer sous le nom 〈〈 BLANKOPHOR™ P 〉〉

This test illustrates the invention and uses a coating sauce according to the invention by mixing:

• 100 parts, expressed as dry matter, composed of 70 parts by dry weight of an aqueous suspension of calcium carbonate Hydrocarb ™ 90ME from the company Omya and 30 parts by dry weight of kaolin Hydragloss ™ 90 from the company Huber.
• 12 parts, expressed as dry matter, of a styrene-acrylic latex marketed by the company BASF under the name 〈〈 ACRONAL ™ S 360 D 〉〉
• 1 part, expressed as dry matter, of a polymer composition according to the invention, called product no. 13
• 1 part, expressed as is, of an optical brightener marketed by the company Bayer under the name 〈〈 BLANKOPHOR ™ P 〉〉

The dry matter content is around 64% and the pH is around 8 to 9 per adjustment with aqueous sodium hydroxide solution.

The polymer composition, according to the invention, called product No. 13, consists 70% by weight of a PVA with an Ostwald viscosity equal to 3.5 mPa.s and a percentage hydrolysis molar equal to 88 measured from the ester index (DIN 53401) and 30% by weight of a copolymer composed of 37% by weight of methacrylic acid and 63% by weight of ethyl acrylate.

The product according to the invention is named in the rest of the product request n ° 13.

Trial # 23

This test illustrates the invention and uses a coating sauce according to the invention by mixing the same constituents as in test No. 22 with the exception of the composition according to the invention.

In this test, the polymer composition, according to the invention, used is product n ° 6 according to the invention.

Trial # 24

This test illustrates the invention and uses a coating sauce according to the invention in mixing the same constituents as in test No. 22 with the exception of the polymer composition according to the invention.

In this test, the polymer composition according to the invention consists of 70% by weight of a PVA of Ostwald viscosity equal to 3 mPa.s and of molar percentage hydrolysis equal to 83 measured from the ester index (DIN 53401) and 30% by weight of a copolymer composed of 37% by weight of methacrylic acid and 63% by weight of ethyl acrylate.

The product according to the invention is called product n ° 14.

Trial # 25

This test illustrates the invention and uses a coating sauce according to the invention in mixing the same constituents as in test No. 22 with the exception of the polymer composition according to the invention.

In this test, the polymer composition according to the invention consists of 70% by weight of a PVA of Ostwald viscosity equal to 5 mPa.s and of molar percentage hydrolysis equal to 88 measured from the ester index (DIN 53401) and 30% by weight of a copolymer composed of 37% by weight of methacrylic acid and 63% by weight of ethyl acrylate.

This product of the invention is called product No. 15.

Trial # 26

This test illustrates the invention and uses a coating sauce according to the invention in mixing the same constituents as in test No. 22 with the exception of the polymer composition according to the invention.

In this test, the polymer composition according to the invention consists of 70% by weight of a PVA of Ostwald viscosity equal to 4 mPa.s and of molar percentage hydrolysis equal to 88 measured from the ester index (DIN 53401) and 30% by weight of a copolymer composed of 37% by weight of methacrylic acid and 63% by weight of ethyl acrylate.

This product of the invention is called product No. 16.

Trial # 27

This test illustrates the invention and uses a coating sauce according to the invention in mixing the same constituents as in test No. 22 with the exception of the polymer composition according to the invention.

In this test, the polymer composition according to the invention consists of 70% by weight of a PVA of Ostwald viscosity equal to 4 mPa.s and of molar percentage hydrolysis equal to 98 measured from the ester index (DIN 53401) and 30% by weight of a copolymer composed of 37% by weight of methacrylic acid and 63% by weight of ethyl acrylate.

This product of the invention is called product No. 17.

Trial # 28

This test illustrates the invention and uses a coating sauce according to the invention in mixing the same constituents as in test No. 22 with the exception of the polymer composition according to the invention.

In this test, the polymer composition according to the invention consists of 70% by weight of a PVA of Ostwald viscosity equal to 3.5 mPa.s and of molar percentage hydrolysis equal to 87.5 measured from the ester index (DIN 53401) and 30% by weight of a homopolymer of acrylic acid.

This product of the invention is called product No. 18.

Essay # 29

This test illustrates the invention and uses a coating sauce according to the invention in mixing the same constituents as in test No. 22 with the exception of the polymer composition according to the invention.

In this test, the polymer composition according to the invention consists of 20% by weight of a PVA of Ostwald viscosity equal to 3.5 mPa.s and of molar percentage hydrolysis equal to 87.5 measured from the ester index (DIN 53401) and 80% by weight of a copolymer composed of 37% by weight of methacrylic acid and 63% by weight of ethyl acrylate.

This product of the invention is called product n ° 19.

Trial # 30

This test illustrates the invention and uses a coating sauce according to the invention in mixing the same constituents as in test No. 22 with the exception of the polymer composition according to the invention.

In this test, the polymer composition according to the invention consists of 40% by weight of a PVA of Ostwald viscosity equal to 3.5 mPa.s and of molar percentage hydrolysis equal to 87.5 measured from the ester index (DIN 53401) and 60% by weight of a copolymer composed of 37% by weight of methacrylic acid and 63% by weight of ethyl acrylate.

This product of the invention is called product No. 20.

Trial # 31

This test illustrates the invention and uses a coating sauce according to the invention in mixing the same constituents as in test No. 22 with the exception of the polymer composition according to the invention.

In this test, the polymer composition according to the invention consists of 60% by weight of a PVA of Ostwald viscosity equal to 3.5 mPa.s and of molar percentage hydrolysis equal to 87.5 measured from the ester index (DIN 53401) and 40% by weight of a copolymer composed of 37% by weight of methacrylic acid and 63% by weight of ethyl acrylate.

This product of the invention is called product n ° 21.

Trial # 32

This test illustrates the invention and uses a coating sauce according to the invention in mixing the same constituents as in test No. 22 with the exception of the polymer composition according to the invention.

In this test, the polymer composition according to the invention consists of 70% by weight of a PVA of Ostwald viscosity equal to 3.5 mPa.s and of molar percentage of hydrolysis equal to 87.5 measured from the ester index (DIN 53401), of 15% in weight of a copolymer composed of 42% by weight of methacrylic acid, 54.1% by weight of ethyl acrylate, 0.8% by weight of n-methylol acrylamide, of 1.6% of ethylene glycol dimethacrylate and 1.5% acrylamide and 15% by weight of a copolymer composed of 37% by weight of methacrylic acid and 63% by weight ethyl acrylate.

This product of the invention is called product No. 22.

The results are collated in Tables IIa. and IIb. below.

As in the previous example, reading Tables IIa. and IIb. shows that only the coating sauces according to the invention exhibit both good whiteness and good retention by using a single product according to the invention at instead of two as in the prior art. Similarly, reading these Tables IIa. and IIb., Shows that the coating sauces according to the invention give the possibility to choose the Brookfield viscosity desired while retaining water retention and activation of optical brighteners.

The conclusion is therefore identical to that of the previous example but for a sauce of coating comprising as pigments calcium carbonate and kaolin.

EXAMPLE III

In a third group of tests No. 33 to No. 43, we repeated, with the same mode procedure and the same material, the operations and measurements of Example I but in replacing the 100 dry parts of calcium carbonate of Example I with 70 parts by dry weight of an aqueous suspension of calcium carbonate Hydrocarb ™ 90ME of Omya and 30 parts by dry weight of talc C10 from Mondo Minerals.

The different tests are:

Trial # 33

• 100 parties, exprimées en matière sèche, composées de 70 parties en poids sec d'une suspension aqueuse de carbonate de calcium Hydrocarb™ 90ME de la société Omya et 30 parties en poids sec de talc C10 de la société Mondo Minerals.
• 12 parties, exprimées en matière sèche, d'un latex styrène-acrylique commercialisé par la société BASF sous le nom 〈〈 ACRONAL™ S 360 D 〉〉
• 0,5 partie, exprimée en matière sèche, d'une solution de PVA commercialisé sous le nom de 〈〈 MOWIOL™ 3 / 83 〉〉 par la société Clariant
• 0,5 partie, exprimée en matière sèche, d'une carboxyméthylcellulose (CMC) commercialisée sous le nom 〈〈 FINNFIX™ 10 〉〉 par la société Metsä Serla.
• 1 partie, exprimée en l'état, d'un azurant optique commercialisé par la société Bayer sous le nom 〈〈 BLANKOPHOR™ P 〉〉

This test illustrates the prior art and uses the following coating sauce by mixing:

• 100 parts, expressed as dry matter, composed of 70 parts by dry weight of an aqueous suspension of calcium carbonate Hydrocarb ™ 90ME from the company Omya and 30 parts by dry weight of talc C10 from the company Mondo Minerals.
• 12 parts, expressed as dry matter, of a styrene-acrylic latex marketed by the company BASF under the name 〈〈 ACRONAL ™ S 360 D 〉〉
• 0.5 part, expressed as dry matter, of a PVA solution marketed under the name of 〈〈 MOWIOL ™ 3/83 〉〉 by the company Clariant
• 0.5 part, expressed as dry matter, of a carboxymethylcellulose (CMC) sold under the name 〈〈 FINNFIX ™ 10 〉〉 by the company Metsä Serla.
• 1 part, expressed as is, of an optical brightener marketed by the company Bayer under the name 〈〈 BLANKOPHOR ™ P 〉〉

The dry matter content is around 64% and the pH is around 8 to 9 per adjustment with aqueous sodium hydroxide solution.

Trial # 34

• 100 parties, exprimées en matière sèche, composées de 70 parties en poids sec d'une suspension aqueuse de carbonate de calcium Hydrocarb™ 90ME de la société Omya et 30 parties en poids sec de talc C10 de la société Mondo Minerals.
• 12 parties, exprimées en matière sèche, d'un latex styrène-acrylique commercialisé par la société BASF sous le nom 〈〈 ACRONAL™ S 360 D 〉〉
• 0,5 partie, exprimée en matière sèche, d'une solution de PVA commercialisé sous le nom de 〈〈 MOWIOL™ 6 / 98 〉〉 par la société Clariant.
• 0,5 partie, exprimée en matière sèche, d'une carboxyméthylcellulose (CMC) commercialisée sous le nom 〈〈 FINNFIX™ 10 〉〉 par la société Metsä Serla.
• 1 partie, exprimée en l'état, d'un azurant optique commercialisé par la société Bayer sous le nom 〈〈 BLANKOPHOR™ P 〉〉

This test illustrates the prior art and uses the following coating sauce by mixing:

• 100 parts, expressed as dry matter, composed of 70 parts by dry weight of an aqueous suspension of calcium carbonate Hydrocarb ™ 90ME from the company Omya and 30 parts by dry weight of talc C10 from the company Mondo Minerals.
• 12 parts, expressed as dry matter, of a styrene-acrylic latex marketed by the company BASF under the name 〈〈 ACRONAL ™ S 360 D 〉〉
• 0.5 part, expressed as dry matter, of a PVA solution sold under the name of 〈〈 MOWIOL ™ 6/98 〉〉 by the company Clariant.
• 0.5 part, expressed as dry matter, of a carboxymethylcellulose (CMC) sold under the name 〈〈 FINNFIX ™ 10 〉〉 by the company Metsä Serla.
• 1 part, expressed as is, of an optical brightener marketed by the company Bayer under the name 〈〈 BLANKOPHOR ™ P 〉〉

The dry matter content is around 64% and the pH is around 8 to 9 per adjustment with aqueous sodium hydroxide solution.

Trial # 35

• 100 parties, exprimées en matière sèche, composées de 70 parties en poids sec d'une suspension aqueuse de carbonate de calcium Hydrocarb™ 90ME de la société Omya et 30 parties en poids sec de talc C10 de la société Mondo Minerals
• 12 parties, exprimées en matière sèche, d'un latex styrène-acrylique commercialisé par la société BASF sous le nom 〈〈 ACRONAL™ S 360 D 〉〉
• 1 partie, exprimée en matière sèche, d'une carboxyméthylcellulose (CMC) commercialisée sous le nom 〈〈 FINNFIX™ 10 〉〉 par la société Metsä Serla
• 1 partie, exprimée en l'état, d'un azurant optique commercialisé par la société Bayer sous le nom 〈〈 BLANKOPHOR™ P 〉〉

This test illustrates the prior art and uses the following coating sauce by mixing:

• 100 parts, expressed as dry matter, composed of 70 parts by dry weight of an aqueous suspension of calcium carbonate Hydrocarb ™ 90ME from the company Omya and 30 parts by dry weight of talc C10 from the company Mondo Minerals
• 12 parts, expressed as dry matter, of a styrene-acrylic latex marketed by the company BASF under the name 〈〈 ACRONAL ™ S 360 D 〉〉
• 1 part, expressed as dry matter, of a carboxymethylcellulose (CMC) sold under the name 〈〈 FINNFIX ™ 10 〉〉 by the company Metsä Serla
• 1 part, expressed as is, of an optical brightener marketed by the company Bayer under the name 〈〈 BLANKOPHOR ™ P 〉〉

The dry matter content is around 64% and the pH is around 8 to 9 per adjustment with aqueous sodium hydroxide solution.

Essay # 36

• 100 parties, exprimées en matière sèche, composées de 70 parties en poids sec d'une suspension aqueuse de carbonate de calcium Hydrocarb™ 90ME de la société Omya et 30 parties en poids sec de talc C10 de la société Mondo Minerals.
• 12 parties, exprimées en matière sèche, d'un latex styrène-acrylique commercialisé par la société BASF sous le nom 〈〈 ACRONAL™ S 360 D 〉〉
• 1 partie, exprimée en matière sèche, d'une solution de PVA commercialisé sous le nom de 〈〈 MOWIOL™ 3 / 83 〉〉 par la société Clariant.
• 1 partie, exprimée en l'état, d'un azurant optique commercialisé par la société Bayer sous le nom 〈〈 BLANKOPHOR™ P 〉〉

This test illustrates the prior art and uses the following coating sauce by mixing:

• 100 parts, expressed as dry matter, composed of 70 parts by dry weight of an aqueous suspension of calcium carbonate Hydrocarb ™ 90ME from the company Omya and 30 parts by dry weight of talc C10 from the company Mondo Minerals.
• 12 parts, expressed as dry matter, of a styrene-acrylic latex marketed by the company BASF under the name 〈〈 ACRONAL ™ S 360 D 〉〉
• 1 part, expressed as dry matter, of a PVA solution sold under the name of 〈〈 MOWIOL ™ 3/83 〉〉 by the company Clariant.
• 1 part, expressed as is, of an optical brightener marketed by the company Bayer under the name 〈〈 BLANKOPHOR ™ P 〉〉

The dry matter content is around 64% and the pH is around 8 to 9 per adjustment with aqueous sodium hydroxide solution.

Essay # 37

• 100 parties, exprimées en matière sèche, composées de 70 parties en poids sec d'une suspension aqueuse de carbonate de calcium Hydrocarb™ 90ME de la société Omya et 30 parties en poids sec de talc C10 de la société Mondo Minerals.
• 12 parties, exprimées en matière sèche, d'un latex styrène-acrylique commercialisé par la société BASF sous le nom 〈〈 ACRONAL™ S 360 D 〉〉
• 1 partie, exprimée en matière sèche, d'un copolymère de l'art antérieur constitué de 37 % en poids d'acide méthacrylique et 63 % en poids d'acrylate d'éthyle et dénommé produit n° 1
• 1 partie, exprimée en l'état, d'un azurant optique commercialisé par la société Bayer sous le nom 〈〈 BLANKOPHOR™ P 〉〉

This test illustrates the prior art and uses the following coating sauce by mixing:

• 100 parts, expressed as dry matter, composed of 70 parts by dry weight of an aqueous suspension of calcium carbonate Hydrocarb ™ 90ME from the company Omya and 30 parts by dry weight of talc C10 from the company Mondo Minerals.
• 12 parts, expressed as dry matter, of a styrene-acrylic latex marketed by the company BASF under the name 〈〈 ACRONAL ™ S 360 D 〉〉
• 1 part, expressed as dry matter, of a copolymer of the prior art consisting of 37% by weight of methacrylic acid and 63% by weight of ethyl acrylate and known as product No. 1
• 1 part, expressed as is, of an optical brightener marketed by the company Bayer under the name 〈〈 BLANKOPHOR ™ P 〉〉

The dry matter content is around 64% and the pH is around 8 to 9 per adjustment with aqueous sodium hydroxide solution.

Essay # 38

• 100 parties, exprimées en matière sèche, composées de 70 parties en poids sec d'une suspension aqueuse de carbonate de calcium Hydrocarb™ 90ME de la société Omya et 30 parties en poids sec de talc C10 de la société Mondo Minerals.
• 12 parties, exprimées en matière sèche, d'un latex styrène-acrylique commercialisé par la société BASF sous le nom 〈〈 ACRONAL™ S 360 D 〉〉
• 1 partie, exprimée en matière sèche, d'une composition polymérique selon l'invention, dénommée produit n° 2
• 1 partie, exprimée en l'état, d'un azurant optique commercialisé par la société Bayer sous le nom 〈〈 BLANKOPHOR™ P 〉〉

This test illustrates the invention and uses a coating sauce according to the invention by mixing:

• 100 parts, expressed as dry matter, composed of 70 parts by dry weight of an aqueous suspension of calcium carbonate Hydrocarb ™ 90ME from the company Omya and 30 parts by dry weight of talc C10 from the company Mondo Minerals.
• 12 parts, expressed as dry matter, of a styrene-acrylic latex marketed by the company BASF under the name 〈〈 ACRONAL ™ S 360 D 〉〉
• 1 part, expressed as dry matter, of a polymeric composition according to the invention, called product No. 2
• 1 part, expressed as is, of an optical brightener marketed by the company Bayer under the name 〈〈 BLANKOPHOR ™ P 〉〉

The dry matter content is around 64% and the pH is around 8 to 9 per adjustment with aqueous sodium hydroxide solution.

Trial # 39

This test illustrates the invention and uses a coating sauce according to the invention in mixing the same constituents as in test No. 38 with the exception of the polymer composition according to the invention.

In this test, the polymer composition, according to the invention, used is product n ° 3 according to the invention.

Trial 40

This test illustrates the invention and uses a coating sauce according to the invention by mixing the same constituents as in test No. 38 with the exception of the polymer composition according to the invention.

In this test, the polymer composition, according to the invention, used is product n ° 4 according to the invention.

Trial # 41

This test illustrates the invention and uses a coating sauce according to the invention by mixing the same constituents as in test No. 38 with the exception of the polymer composition according to the invention.

In this test, the polymer composition, according to the invention, used is product No. 5 according to the invention.

Trial # 42

This test illustrates the invention and uses a coating sauce according to the invention by mixing the same constituents as in test No. 38 with the exception of the polymer composition according to the invention.

In this test, the polymer composition, according to the invention, used is product n ° 6 according to the invention.

Trial # 43

This test illustrates the invention and uses a coating sauce according to the invention by mixing the same constituents as in test No. 38 with the exception of the polymer composition according to the invention.

In this test, the polymer composition, according to the invention, used is product n ° 7 according to the invention.

The results are collated in Tables IIIa. and IIIb. below.

Reading Tables IIIa. and IIIb. leads to the same conclusions as those Tables I or II but this time for a coating sauce comprising a charge composed of calcium carbonate and talc.

Examples 34 and 42 being differentiated by the use of a single product for test n ° 42 according to the invention while two products are used in the test No. 34 of the prior art.

EXAMPLE IV

This example concerns the tests on the variation of the type of optical brightener.

• 70 parties, exprimées en matière sèche, d'une suspension aqueuse de carbonate de calcium Hydrocarb™ 90ME de la société Omya
• 30 parties, exprimées en matière sèche de kaolin Hydragloss™ 90 de la société Huber
• 12 parties, exprimées en matière sèche, d'un latex styrène-acrylique commercialisé sous le nom Acronal™ S 360 D par la société BASF.
• 1 partie, exprimée en matière sèche, du produit n° 6 selon l'invention.
• 1 partie, exprimée en l'état, des différents azurants optiques à tester, sauf pour l'essai n° 44 constituant un essai témoin dans lequel il n'est mis en oeuvre aucun azurant optique,
  la teneur en matière sèche étant de l'ordre de 64 % et le pH maintenu entre 8 et 9 avec une solution aqueuse d'hydroxyde de sodium.

For this purpose, the coating sauces to be tested are prepared by mixing:

• 70 parts, expressed as dry matter, of an aqueous suspension of calcium carbonate Hydrocarb ™ 90ME from the company Omya
• 30 parts, expressed as dry matter of Huag Hydragloss ™ 90 kaolin
• 12 parts, expressed as dry matter, of a styrene-acrylic latex sold under the name Acronal ™ S 360 D by the company BASF.
• 1 part, expressed as dry matter, of product No. 6 according to the invention.
• 1 part, expressed as is, of the various optical brighteners to be tested, except for test No. 44 constituting a control test in which no optical brighteners are used,
  the dry matter content being of the order of 64% and the pH maintained between 8 and 9 with an aqueous solution of sodium hydroxide.

The different optical brighteners are:

Trial 45

The optical brightener sold by the company Bayer under the name Blankophor ™ P.

Trial # 46

The optical brightener sold by the Clariant company under the name Leucophor ™ CK.

Trial # 47

The optical brightener sold by the company Bayer under the name of Blankophor ™ PSK.

Trial # 48

The optical brightener sold by the company 3V Sigma under the name of Optiblanc ™.

Essay # 49

The optical brightener sold by the company Ciba under the name of Tinopal ™ ABP.

Trial # 50

The optical brightener sold by the company Ciba under the name of Tinopal ™ STP.

Essay # 51

The optical brightener sold by the company Ciba under the name of Tinopal ™ SPP.

Essay # 52

The optical brightener sold by the company Ciba under the name of Tinopal ™ UP.

Essay # 53

The optical brightener sold by the company Ciba under the name of Tinopal ™ SK.

These different coating sauces according to the invention are then the subject of the viscosity, water retention and whiteness according to the same procedures as for previous tests.

Essai n° Invention Invention Invention Invention 50 51 52 53 Charge : CaCO3 (en part en sec) 70 70 70 70 Charge : Kaolin (en part en sec) 30 30 30 30 Liant : Latex styrène acrylique (en part en sec) 12 12 12 12 Rétenteur /activateur (en part en sec) : Produit n° 6 1 1 1 1 Azurant (en part en état) Blankophor P Leucophor CK Blankophor PSK Optiblanc Tinopal ABP Tinopal STP 1 Tinopal SPP 1 Tinopal UP 1 Tinopal SK 1 pH Extrait sec % 8,7 8,8 8,5 8,6 63,8 64,1 64,0 63,9 Viscosité Brookfield (cP) 10 tr/min 8800 8200 7300 10000 100 tr/min 1620 1520 1260 1820 Rétention d'eau Vol en 20min 1.6 ml 1.7 ml 1.5 ml 1.6 ml Blancheur R 457 nm (Data color 3000) 100% UV 90,2 91,1 95,9 99,5 The results are collated in Tables IVa. and IVb. following.

Test No. Invention Invention Invention Invention 50 51 52 53 Load: CaCO3 (dry share) 70 70 70 70 Load: Kaolin (dry share) 30 30 30 30 Binder: Acrylic styrene latex (dry part) 12 12 12 12 Retentor / activator (dry part): Product n ° 6 1 1 1 1 Brightener (in part in state) Blankophor P Leucophor CK Blankophor PSK Optiblanc Tinopal ABP Tinopal STP 1 Tinopal SPP 1 Tinopal UP 1 Tinopal SK 1 pH dry extract % 8.7 8.8 8.5 8.6 63.8 64.1 64.0 63.9 Brookfield viscosity (cP) 10 rpm 8800 8200 7300 10,000 100 rpm 1620 1520 1260 1820 Water retention Flight in 20min 1.6 ml 1.7 ml 1.5 ml 1.6 ml Whiteness R 457 nm (Data color 3000) 100% UV 90.2 91.1 95.9 99.5

Reading Tables IVa. and IVb. shows that whatever the brightener optics used, the polymer composition according to the invention allows increase whiteness under UV while retaining water retention.

EXAMPLE V

In this example which illustrates the invention, the proportion of composition is varied polymer based on the amount of optical brightener used in the sleeping.

For this purpose, the coating sauces to be tested are prepared according to the same procedure, with the same material and the same quantities of the various constituents as in the previous example, except for the amounts of optical brightener and composition polymer according to the invention which vary for the various tests.

Essay # 54

This test, illustrating the invention, uses 0.6 parts, expressed as it is, of a brightener optical sold by Ciba under the name of Tinopal ™ ABP and 0.6 part of the product No. 6 according to the invention.

Trial 55

This test, illustrating the invention, uses 0.6 parts, expressed as it is, of a brightener optical sold by Ciba under the name of Tinopal ™ ABP and 0.8 part of the product No. 6 according to the invention.

Essay # 56

This test, illustrating the invention, uses 0.6 parts, expressed as it is, of a brightener optical sold by Ciba under the name of Tinopal ™ ABP and 1.0 part of the product No. 6 according to the invention.

Essay # 57

This test, illustrating the invention, uses 0.6 parts, expressed as it is, of a brightener optical sold by the company Ciba under the name of Tinopal ™ ABP and 1.2 parts of the product No. 6 according to the invention.

Trial # 58

This test, illustrating the invention, uses 0.8 parts, expressed as it is, of a brightener optical sold by Ciba under the name of Tinopal ™ ABP and 0.6 part of the product No. 6 according to the invention.

Trial # 59

This test, illustrating the invention, uses 0.8 parts, expressed as it is, of a brightener optical sold by Ciba under the name of Tinopal ™ ABP and 0.8 part of the product No. 6 according to the invention.

Trial # 60

This test, illustrating the invention, uses 0.8 parts, expressed as it is, of a brightener optical sold by Ciba under the name of Tinopal ™ ABP and 1.0 part of the product No. 6 according to the invention.

Trial # 61

This test, illustrating the invention, uses 0.8 parts, expressed as it is, of a brightener optical sold by the company Ciba under the name of Tinopal ™ ABP and 1.2 parts of the product No. 6 according to the invention.

Essay # 62

This test, illustrating the invention, uses 1.0 part, expressed as it is, of a brightener optical sold by Ciba under the name of Tinopal ™ ABP and 0.6 part of the product No. 6 according to the invention.

Trial # 63

This test, illustrating the invention, uses 1.0 part, expressed as it is, of a brightener optical sold by Ciba under the name of Tinopal ™ ABP and 0.8 part of the product No. 6 according to the invention.

Essay # 64

This test, illustrating the invention, uses 1.0 part, expressed as it is, of a brightener optical sold by Ciba under the name of Tinopal ™ ABP and 1.0 part of the product No. 6 according to the invention.

Trial # 65

This test, illustrating the invention, uses 1.0 part, expressed as it is, of a brightener optical sold by the company Ciba under the name of Tinopal ™ ABP and 1.2 parts of the product No. 6 according to the invention.

Essay # 66

This test, illustrating the invention, uses 1.2 parts, expressed as is, of a optical brightener sold by Ciba under the name of Tinopal ™ ABP and 0.6 part of the product n ° 6 according to the invention.

Essay # 67

This test, illustrating the invention, uses 1.2 parts, expressed as is, of a optical brightener sold by Ciba under the name of Tinopal ™ ABP and 0.8 part of the product n ° 6 according to the invention.

Essay # 68

This test, illustrating the invention, uses 1.2 parts, expressed as is, of a optical brightener sold by Ciba under the name Tinopal ™ ABP and 1.0 part of product n ° 6 according to the invention.

Essay # 69

This test, illustrating the invention, uses 1.2 parts, expressed as is, of a optical brightener sold by Ciba under the name Tinopal ™ ABP and 1.2 parts of product n ° 6 according to the invention.

Essai n° 64 65 66 67 68 69 Charge : CaCO3 (en part en sec) 70 70 70 70 70 70 Charge : Kaolin (en part en sec) 30 30 30 30 30 30 Liant : Latex styrène acrylique (en part en sec) 12 12 12 12 12 12 Rétenteur /activateur (en part en sec) : Produit n° 6 1,0 1,2 0,6 0,8 1,0 1,2 Azurant (en part en état) 1,0 1,0 1,2 1,2 1,2 1,2 pH Extrait sec % 8,5 8,6 8,6 8,5 8,6 8,7 63,8 64,0 63,9 63,8 64,0 64,0 Viscosité Brookfield (cP) 10 tr/min 3920 4920 3840 1920 4080 4600 100 tr/min 960 1150 720 610 910 1130 Rétention d'eau Vol en ml en 20min 2,1 1,9 2,6 2,4 2,1 2 Blancheur R 457 nm (Data color 3000) Avec UV 89,6 89,9 89,3 89,5 90,1 90,4 The results are collated in Tables Va. and Vb. below.

Test No. 64 65 66 67 68 69 Load: CaCO3 (dry share) 70 70 70 70 70 70 Load: Kaolin (dry share) 30 30 30 30 30 30 Binder: Acrylic styrene latex (dry part) 12 12 12 12 12 12 Retentor / activator (dry part): Product n ° 6 1.0 1.2 0.6 0.8 1.0 1.2 Brightener (part in state) 1.0 1.0 1.2 1.2 1.2 1.2 pH dry extract % 8.5 8.6 8.6 8.5 8.6 8.7 63.8 64.0 63.9 63.8 64.0 64.0 Brookfield viscosity (cP) 10 rpm 3920 4920 3840 1920 4080 4600 100 rpm 960 1150 720 610 910 1130 Water retention Flight in ml in 20min 2.1 1.9 2.6 2.4 2.1 2 Whiteness R 457 nm (Data color 3000) With UV 89.6 89.9 89.3 89.5 90.1 90.4

Reading the Tables Va. and Vb. shows that whatever the dose of optical brightener used, the polymer composition according to the invention allows increase whiteness under UV while retaining water retention.

EXAMPLE VI

In this example which illustrates the invention, the nature of the binder is varied.

For this purpose, the coating sauces to be tested are prepared according to the same procedure, the same material and the same quantities of the various constituents as in Example IV, with the exception of the nature of the latex used in the various tests, as well as the products intended to act as water retentants and / or activators of optical brighteners.

Trial n ° 70

This test, which describes the prior art, implements a successive addition of 0.5 part, expressed as dry matter, of a PVA solution marketed under the name of 〈〈 MOWIOL ™ 3/83 〉〉 by the company Clariant and 0.5 part, expressed as dry matter, of CMC and 12 parts, expressed as dry matter, of an acrylic styrene latex marketed under the name of "Acronal ™ S 360 D" by the company BASF.

Trial n ° 71

This test, which describes the invention, uses 1 part, expressed as dry matter, of product n ° 6 according to the invention, as well as 12 parts, expressed as dry matter, of a latex acrylic styrene sold under the name of Acronal ™ S 360 D by the company BASF.

Trial # 72

This test, which describes the prior art, implements a successive addition of 0.5 part, expressed as dry matter, of a PVA solution marketed under the name of 〈〈 MOWIOL ™ 3/83 〉〉 by the company Clariant and 0.5 part, expressed as dry matter, of CMC and 12 parts, expressed as dry matter, of a styrene butadiene latex marketed under the name DL 980 by the company Dow Chemical and referenced here under the name styrene-butadiene 1.

Essay # 73

This test, which describes the invention, uses 1 part, expressed as dry matter, of product n ° 6 according to the invention, as well as 12 parts, expressed as dry matter, of a latex styrene-butadiene sold under the name DL 980 by the company Dow Chemical and referenced here under the name styrene-butadiene 1.

Trial # 74

This test, which describes the prior art, implements a successive addition of 0.5 part, expressed as dry matter, of a PVA solution marketed under the name of 〈〈 MOWIOL ™ 3/83 〉〉 by the company Clariant and 0.5 part, expressed as dry matter, of CMC and 12 parts, expressed as dry matter, of a styrene butadiene latex marketed under the name of Rhodopas ™ SB 123 by the company Rhône-Poulenc and referenced here under the name styrene-butadiene 2.

Trial # 75

This test, which describes the invention, uses 1 part, expressed as dry matter, of product n ° 6 according to the invention, as well as 12 parts, expressed as dry matter, of a latex styrene-butadiene sold under the name Rhodopas ™ SB 123 by the company Rhône-Poulenc and referenced here under the name styrene-butadiene 2.

The results are collated in Table VI below.

Reading Table VI shows that it is possible to increase the whiteness under UV while retaining water retention whatever the latex used works in the coating sauce.

The invention also relates to the use, in the preparation of coating sauces paper mills, stable liquid polymeric aqueous compositions ensuring the function optical brightener activator, water retention and viscosity regulator coating sauces, containing at least one polyvinyl alcohol (PVA) and at least one water-soluble polymer at neutral or alkaline pH.

The invention also relates to papermaking coating sauces of the type containing a filler, a polymeric binder, water retentants, pigments, optical brighteners, and various other papermaking additives, and suitable mixtures of these additives according to the knowledge of a person skilled in the art, characterized in that water retention, activation of optical brighteners and viscosities are controlled by a composition stable liquid polymeric aqueous containing at least one polyvinyl alcohol (PVA) and at least one water-soluble polymer at neutral or alkaline pH.

Claims (17)

Aqueous polymeric composition, liquid and stable, for regulating the activation of optical brighteners, water retention and viscosities of paper coating sauces, containing at least one polyvinyl alcohol (PVA) and at least one water-soluble polymer at neutral pH or alkaline, characterized in that said PVA presents: an Ostwald viscosity of less than 5 mPa.s, corresponding to a degree of polymerization of less than 600, and a molar percentage of hydrolysis between 70 and 100 measured from the ester number (DIN 53401) corresponding to a molar percentage of vinyl acetate units between 30 and 0. Aqueous polymeric composition, liquid and stable, for regulating the activation of optical brighteners, water retention and viscosities of paper coating sauces, containing at least one polyvinyl alcohol (PVA) and at least one water-soluble polymer at neutral pH or alkaline, according to claim 1, characterized in that said PVA presents: an Ostwald viscosity of between 2 mPa.s and 4 mPa.s, corresponding to a degree of polymerization from 250 to 500, and a molar percentage of hydrolysis between 80 and 90 measured from the ester number (DIN 53401) corresponding to a molar percentage of vinyl acetate units between 20 and 10. Aqueous polymeric composition, liquid and stable, allowing to regulate activation of optical brighteners, water retention and viscosities of sauces paper coating, containing at least one polyvinyl alcohol (PVA) and at least a water-soluble polymer at neutral or alkaline pH, according to any one of Claims 1 or 2, characterized in that it contains a percentage of PVA more than 20% by weight. Aqueous polymeric composition, liquid and stable, allowing to regulate activation of optical brighteners, water retention and viscosities of sauces paper coating, containing at least one polyvinyl alcohol (PVA) and at least a water-soluble polymer at neutral or alkaline pH, according to claim 3, characterized in that it contains a percentage of PVA greater than 50% in weight. Aqueous polymeric composition, liquid and stable, allowing to regulate activation of optical brighteners, water retention and viscosities of sauces paper coating, containing at least one polyvinyl alcohol (PVA) and at least a water-soluble polymer at neutral or alkaline pH, according to any one of Claims 1 to 4, characterized in that the water-soluble polymer is a dispersion copolymer containing more than 20% by weight of monomer having acid groups. Aqueous polymeric composition, liquid and stable, allowing to regulate activation of optical brighteners, water retention and viscosities of sauces paper coating, containing at least one polyvinyl alcohol (PVA) and at least a water-soluble polymer at neutral or alkaline pH, according to claim 5, characterized in that the water-soluble copolymer is a dispersion copolymer containing from 20% to 75% by weight of monomer containing acid groups. Aqueous polymeric composition, liquid and stable, allowing to regulate activation of optical brighteners, water retention and viscosities of sauces paper coating, containing at least one polyvinyl alcohol (PVA) and at least a water-soluble polymer at neutral or alkaline pH, according to one of claims 5 or 6, characterized in that the acid groups are carboxylic groups. Aqueous polymeric composition, liquid and stable, allowing to regulate activation of optical brighteners, water retention and viscosities of sauces paper coating, containing at least one polyvinyl alcohol (PVA) and at least a water-soluble polymer at neutral or alkaline pH, according to one of claims 1 to 7, characterized in that the emulsion copolymer is chosen from among copolymers of at least one of the acid-functional monomers such as acid acrylic and / or methacrylic, itaconic, citraconic, crotonic, fumaric, maleic, isocrotonic, mesaconic, sinapic, undecylenic, angelic and / or their respective anhydrides and / or the hemiesters of the diacids, acrylamido-methyl-propane-sulfonic acid, the acid phosphates or sulfates of the acrylates and ethylene glycol methacrylates, propylene glycol, butylene glycol, polyethylene glycol, polypropylene glycol and polybutylene glycol with at least one of monomers without an acid group such as derivatives of the abovementioned acids as well as methyl, ethyl, butyl, 2-ethyl-hexyl acrylates or methacrylates, or else among acrylonitrile, methacrylonitrile, acrylamide, methacrylamide, n-methylolacrylamide, and optionally with vinyl monomers and / or styrenics such as vinyl acetate, styrene, methylstyrene, diisobutylene, divinylbenzene, methylvinyl ether or even vinylcaprolactam or mixtures thereof or with one of the monomers oxyalkylated ethylenically unsaturated terminated by a chain, linear or branched, such as linear or branched alkyl, aryl, alkylaryl, arylalkyl groups having from 1 to 50 carbon atoms and in particular the di-, tri- and tetrastyrylphenol groups, nonylphenols or finally with at least one of the monomers having at least two ethylenic unsaturations such as ethylene glycol dimethacrylate, trimethylolpropanetriacrylate, allyl acrylate, methylene-bis-acrylamide, methylene-bis-methacrylamide, tetrallyloxyethane, triallylcyanurate, allyl ethers obtained from polyols such as pentaerythritol, sorbitol, sucrose or mixtures thereof. Aqueous polymeric composition, liquid and stable, allowing to regulate activation of optical brighteners, water retention and viscosities of sauces paper coating, containing at least one polyvinyl alcohol (PVA) and at least a water-soluble polymer at neutral or alkaline pH, according to any one of Claims 1 to 4, characterized in that it contains a polyurethane water soluble. Aqueous polymeric composition, liquid and stable, allowing to regulate activation of optical brighteners, water retention and viscosities of sauces paper coating, containing at least one polyvinyl alcohol (PVA) and at least a water-soluble polymer at neutral or alkaline pH, according to any one of Claims 1 to 4, characterized in that the water-soluble polymer is a homopolymer or a copolymer in solution of a carboxylic acid. Aqueous suspension or slurry of mineral filler containing the compositions stable liquid polymeric aqueous ensuring the activation function of optical brighteners, the water retention function as well as the regulation function the viscosity of the paper coating sauces, according to any one of the claims 1 to 10. Aqueous suspension or slurry of mineral filler containing the compositions stable liquid polymeric aqueous ensuring the activation function of optical brighteners, the water retention function as well as the regulation function the viscosity of paper coating sauces according to claim 11 characterized in that the mineral filler is chosen from carbonates of natural calcium such as chalk, calcite, marble or carbonates of synthetic calcium, dolomites, kaolins, talc, titanium dioxide, white satin, mica, calcined clay, aluminum hydroxide, calcium sulfate or their mixtures. Use of the stable liquid polymeric aqueous compositions according to one of claims 1 to 10 in the preparation of paper coating sauces. Use of aqueous mineral charge suspensions according to one of the Claims 11 and 12 in the preparation of paper coating sauces. Paper coating sauce containing the aqueous polymeric compositions liquids ensuring the activation function of optical brighteners the function of water retention as well as the viscosity regulation function of sauces paper coating, according to any one of claims 1 to 10. Paper coating sauce containing the aqueous suspension or charge slurry mineral according to one of claims 11 or 12. Sheet of coated paper containing the paper coating sauce according to one of claims 15 or 16.

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