FI121969B - wallpaper Paper - Google Patents

Description

wallpaper Paper

The present invention relates to a wallpaper paper comprising a fibrous base paper having first and second surfaces and a barrier layer 5 on a first surface side of the base paper.

This application relates to wallpaper paper suitable for use in that an adhesive, usually wallpaper paste, is applied to the wall to be wallpapered and the dry wallpaper is placed over an adhesive layer. This ta-10 method of predation is called "paste-the-wall" in English.

The problem with wood-based wallpaper paper is that it expands in the width direction of the web when the paper dampens from the adhesive. Width expansion in the width direction is the result of fiber orientation in the web. In the web, the fibers tend to orient in the longitudinal direction of the web. When wetted, the wood fibers swell in the transverse direction of the fiber, whereby the web expands in the width direction of the web. Typically, the wet expansion of fibrous base papers is in the order of 1.5-2%.

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Nowadays, wallpapering is usually done using a butt seam, whereby the consequences of the wet-width expansion are readily apparent. Enlargement will result in poor wallpapering results; butt seams expand and wrinkles are killed. In contrast to the conventional wall-papering method, where the wallpapering is done by applying a paste to the backing of the wallpaper paper and only after a certain drying time (10-15 minutes) g, the wallpaper is fixed to the wall, whereby There is no curing time in the wallpapering method. As a result, ^ 30 this wallpapering technique requires an almost non-widening web, £ because of the wetting of the wallpaper and the subsequent wet expansion

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and simultaneous adherence to the wall can easily ΪΙ lead to the above problems in wallpapering.

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™ 35 Attempts have been made to solve the problem of wet expansion by using a nonwoven fabric consisting of synthetic fibers and a binder such as latex as the base material for the wallpaper. Nonwovens-based products do achieve a wet expansion of about 0.2% 2, but in some respects nonwovens are a poor alternative. It has poor opacity, is difficult to print on a rough surface (missing dots), and difficult to recycle nonwovens comprising synthetic fibers and a latex binder therebetween. The waste paper formed in the base paper production process cannot be recycled in the manufacturing process, but is dumped.

The wet-expansion tendency of wood-based wallpaper paper can be reduced by treating the base paper with a hydrophobic adhesive or, for example, cross-linking chemicals (fiber-cross-linking), but these treatments, when combined, do not give a satisfactory result. In addition, if the adhesive used for fixing the wallpaper has a high pH (11 or above) and low surface tension, hydrophobization cannot prevent rapid wetting of the fibers. The hydrophobic layer is destroyed. The low surface tension of the wallpaper paste thus places special demands on the surface treatment layers of the base paper.

According to the applicant's 20 experience, no single treatment can achieve the wet-wet stability of wood-based wallpaper paper. The dimensional stability required by the "Paste-the-wall" wallpapering method requires a combination of more than one layer. In addition to dimensional stability, the wallpaper must have movability when wall-mounted (positioning) and then sufficient adhesion to various wall materials (wall-to-wall depth). Multi-layer solutions also have their own problems, for example, when experimenting with more porous and barrier coating layers under the barrier layer, a good dimensional stability of the coating with a large amount of latex was found, but the wallpaper was too easy to remove from the wall. The coating layer did not adhere well to either the ^ 30 base paper or the wall.

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On the other hand, the wallpaper must not be too dense, since the water vapor must also be able to escape partially as the adhesive dries on the wall.

LT) g These requirements limit the solutions available to prevent wet expansion. In addition, the choice of processing agents is limited, for example, by the severe yellowing of certain substances / combinations of substances or by product safety considerations.

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The wallpaper paper according to the invention is characterized in that the wallpaper paper comprises a hydrophilic layer between the first surface and the barrier layer, or on the barrier layer, and the hydrophilic layer 5 consists of polyvinyl alcohol and a filler, or the hydrophilic layer comprises crosslinked polyvinyl alcohol.

The wallpaper paper according to the invention comprises a wood fiber based base paper having first and second surfaces. The first surface 10 of the base paper is on the side of the wall, and the other surface has wallpaper printing and / or other patterning. The base paper may be single or double ply. Preferably, the base paper does not contain synthetic fibers, but the fiber portion of the base paper comprises mechanical and / or chemical pulp.

When the wallpaper paper according to the invention is mounted on a wall, an adhesive layer is applied between the paper and the wall which has been applied to the wall prior to the application of the wallpaper paper. Thus, in this application, no layer to be applied to wallpaper paper means a layer of adhesive, since the actual adhesive is applied to the wall. In addition to the layers disclosed in this application, the wallpaper paper 20 may also have an adhesive layer if it is desired to incorporate the adhesive into the product, eliminating the need to apply adhesive to the wall, for example by simply wetting the adhesive.

25 Wet expansion is achieved by applying two different functional finishing technologies. Prior to these surface treatments, the base-g peri may be strongly hydrophobic-bonded at the wet end of the papermaking machine. The idea of the invention is that the barrier

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o the functionality of the layer is improved by the water absorbent layer.

^ 30 Em. the layer alone, when applied, could not adequately prevent wet expansion, but when applied over or under the barrier layer, the wallpaper paper was rendered wet-expanded or the wet-expansion riitt was sufficiently reduced. The treatment layers of the wallpaper paper according to the invention are formed using known paper coating techniques, mainly by brushing.

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The first alternative is to apply a barrier layer to the first surface of the base paper, which slows down the penetration of water from the adhesive into the base paper. A number of different substances having the ability to prevent water / water vapor permeability can be used in the barrier layer, although the choice of each substance is limited e.g. yellowing of certain substances or combinations of substances, or product safety aspects. The barrier layer may be, for example, styrene acrylate, polyacrylate, styrene butadiene, polyvinyl acetate or ethyl vinyl acetate. The barrier layer may also be a mixture of several substances.

A hydrophilic layer is formed on the surface of this barrier layer which is capable of absorbing the water contained in the adhesive under anal conditions. However, the hydrophilic layer can be dried under neutral conditions on the surface of the barrier layer during manufacture. The hydrophilic layer 15 may be, for example, a cross-linked polyvinyl alcohol hydrogel. Polyvinyl alcohol can be crosslinked, for example, by treatment with boric acid. Polyvinyl alcohol also improves the adhesion of the wallpaper to the wall. The base paper produced in accordance with this embodiment of the invention had a wet spread of 0% when the application rate of the barrier layer was 10-13 g / m 2 and the application rate of the hydrophilic layer was 13-17 g / m 2.

The polyvinyl alcohol used in the hydrophilic layer may be selected from fully hydrolyzed, superhydrolyzed or pre-crosslinked, fully hydrolyzed or superhydrolyzed polyvinyl alcohols. By fully hydrolyzed is meant a degree of hydrolysis of 99-100%. Degree of hydrolysis refers to the amount of alkali solution added by pulverization of vinyl alcohol by saponification from polyvinyl acetate.

™ A decrease in the degree of hydrolysis means an increase in the hydrophilicity of polyvinyl alcohol 9.

30 g Hydrophilicity can be calculated by controlled heat treatment of poly-

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increasing the crystallinity of the vinyl alcohol or cross-linking the dusty vinyl alcohol with, for example, boric acid, borax, glyoxal, g urea or melamine resin.

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Polyvinyl alcohol may also be pre-crosslinked. The cross-linked cross-linked polyvinyl alcohols may have undergone borax or boric acid treatment. Borax or boric acid treatment increases the viscosity and tackiness / adhesion properties of the treatment solution. As a result of the treatment, the penetration of polyvinyl alcohol into the paper is reduced, whereby PVA remains on the paper surface and gives a uniform layer thickness.

5

Another alternative is to first form a water-binding hydrophilic layer on the first surface of the base paper and a barrier layer on the surface of the hydrophilic layer. The operation of the various layers is similar to that described above, and the materials used to form the layers are also the same. A particular advantage of this option, in which the barrier layer is in contact with the adhesive, is that the wallpaper is easily movable on the wall, i.e. the wall-mounting of the wallpaper is facilitated. The wet paper expansion of the second alternative wallpaper paper was 0.13-0.34% with a hydrophilic layer application rate of 9 g / m 2 and a barrier layer application rate of 9 to 15 g / m 2.

In the third alternative of the invention, the operating conditions of the barrier layer are improved by sealing the base before applying the barrier layer. The bottom sealing prevents the barrier polymer from pe-20 becoming net to the bottom, resulting in a smoother barrier layer on the surface. In this third alternative, a surface-sealing, polyvinyl alcohol-containing filler coating, such as kaolin, is first applied to the first surface of the wallpaper paper, and a barrier layer is applied thereto. When a filler such as kaolin or talc is used, the amount of polyvinyl alcohol combined with the polyvinyl alcohol can be reduced and the runnability and dehydration are improved by the addition of the filler. g Polyvinyl alcohol forms the hydrophilic portion of the layer. A sheet-like filler, such as kaolin, is best suited for use, preferably has a shape factor of at least 70. With a low coating of 30 g (8 g / m 2), with a barrier layer saavut (10 g / m 2) applied thereto, a non-wetted product was achieved. With kaolin

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and a hydrophilic layer comprising polyvinyl alcohol and a barrier layer were further combined with a layer comprising polyvinyl alcohol

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§ the cross-linking treatment (e.g. with Fixapret) could be reduced by 2 g / m 2 (10 to 8 g / m 2).

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According to an alternative of the invention, a filler such as kaolin or talc may also be used in the barrier layer.

In any of the surface treatment solutions of the invention, it is preferred that the base paper be highly hydrophobic, for example by resin, AKD (alkyl ketene dimer) or ASA (alkenyl succinic anhydride) bonding at the wet end of the paper machine.

Example 1.

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An experiment was made in which various barrier and hydrophilic layers were formed on the side of the base paper which, when wallpapering, comes against the wall. A polyacrylate (Cellfob 18, Cellkem Oy, Finland) was used as the barrier layer forming agent. Cross-linked polyvinyl alcohol (Celanese Cellvol MM-14, Noviani) or a mixture of polyvinyl alcohol, kaolin and resin (69/25/6 Kuraray PVA 105 (supplied by Algol) / Capim NP (supplied by Imerys Minerals) / Cellcoat 60) was used as the hydrophilic layer. (edited by Cellkem) Celvol MM-14 is a boronic acid treated Cellcoat 6040 is a polymeric 20 resin-water polymeric solution containing reactive hydroxyl groups containing 18% by weight of glyoxal as a crosslinker.

A solution for cross-linking polyvinyl alcohol (Cellvol MM-14) was prepared as follows: The powder was mixed with water at about 25 ° C. The temperature was raised with steam heating to 91 ° C and held for 30 min. The temperature had to stay below 96 ° C all the time.

A mixture of polyvinyl alcohol, kaolin and resin was prepared as follows: o The polyvinyl alcohol powder was mixed with water at a temperature of about 30 ° C to 25 ° C. The temperature was raised to 91 ° C with steam and maintained at 110 ° C for 110 min. To the above solution, kaolin and resin were added with stirring as the temperature of the solution was lowered / cooled to about 30 ° C.

tn sj-c3 35 Cresta D2 (Μ-Real, Finland) was used as the base paper. The base paper had a basis weight of 120 g / m2. The base paper grade is of two layers, the first layer coming from the wall is mechanical mas 7 and the second layer is chemical pulp. The second layer has a double coating on its surface.

The barrier layer and hydrophilic layer were formed by a groove bar cover 5. The recipes used are tabulated in Tables 1 and 2, and the test results obtained are tabulated in Tables 3 and 4.

In addition to the laboratory results, the test was carried out on a gypsum board surface using a starch based adhesive (Solvite ES, Henkel).

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From the results of Tables 3 and 4, it is seen that the best results are obtained with a hydrophilic layer between the barrier layer of polyacrylate and the base paper, which is either a cross-linked polyvinyl alcohol hydrogel or a mixture of polyvinyl alcohol, kaolin and N8, N8,

The following abbreviations are used in Tables 3 and 4: yp = top, tp = backside, hand = treatment conditions, norm = normal, drains = drained, air = air, MVTR = water vapor transmission rate.

Table 1. Compositions of the surface treatment layers of samples Ref.1 and N1 to N5. The hydrophilic layer is against the wall, i.e. in contact with the adhesive.

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Surface treatment layer__Ref.1 N1 N2__N3 N4 N5

Barrier layer, g / m2 _______ 5 Cellfob 18_0__11 11 + 11 _11__11__11_ ^ Hydrophilic layer, g / m2 _______ S Cellvol MM -14 0 4 6 9 i x Table 2. Compositions of surface treatment layers of samples Ref.2 and N6-N13. The barrier layer is against the wall, i.e. 'in contact' with the adhesive.

5 30 _ o Surface treatment layer__Ref.2 N6 N7 N8 N9 N10 N11 N12 N13 ^ Hydrophilic layer, g / m2 __________

Cellvol MM-14__0__4_7_4_7 ____

Kuraray PVA 105 + 0______4__8__4__8_ _ 8

Capim NP kaolin +

Cellcoat 6040__________

Barrier layer, g / m2 __________ ~ CeNfob 18 | θ 12 | 13 | 12 | 12

Table 3. Test results for samples Ref.1 and N1-N5. The hydrophilic layer is against the wall.

__Reference 1 N1__N2__N3__N4__N5_ Total Coating__0__11_22__15__17__20_

Neliömassa__120__132__143__137__139__143

Cobb 300 S, tp, norm / currency 31/80 6__1 / 32 1_2__5_

Cobb 300 s, pH 11, _tp_ 34/104 17_ 3/62 5__0__0_

Cobb 300 sec, hand

120 C / 60 s, tp 33__6__1_2_2_2_ MVTR, p / m2 / 24h / 50% 380__190 49__11_3.7 2.5 MVTR, art. 120 C / 60s, g / m2 / 24h / 50% 370__170 42__10_3.0 2.3 Wet Exp. %, 1 + 1 min__T67__1.25 0.83 0.83 0.87 0.42 Curve rev, mm, yp / tp__11 yp__4tg__6tg__5tg__4tg__6tp_

Brightness, tp_67 \ 2_ 62.8 60.6 62.5 62.5 62.6

Brightness, hand. 120 C / 60S, tp_66J_ 60.8 58.6 60.5 60.2 60.2 Wet Expansion Wall%, Gyproc,

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Example 2.

Various alternatives to the hydrophilic layer were tested under laboratory conditions. The samples were measured for wet expansion.

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Table 5. Wet expansion values of treated paper.

Polyvinyl alcohol__Application rate (g / m2) Wet expansion (%)

Celvol 103_J3J__0,30_ _J_6J__0J_8_

Celvol 125_UJ $ __ 0,09_ _JI3J3__0I22_ _λ§Α__0J0_

Celvol 165_JJJ3__0J7_ _J3J__0J3_ _J_M__0J_3_

Celvol 350_JU3_JVI3_ _J ^ 5__0J_3_ _J5J__0J7_

Celvol MM-14_JMJ3_Ml_ _12J5__0J_3_ _: 16.8__0J_8_

Celvol MM-51_1 ^ 0_0J3_ 15.1 0.17 o Celvol 103 is a fully hydrolysed, low molecular weight 8-10 polyvinyl alcohol. Celvol 125 is a superhydrolyzed low molecular weight polyvinyl alcohol. Celvol 165 is a superhydrolyzed, high molecular weight polyvinyl alcohol. Celvol 350 is a £ fully hydrolyzed high molecular weight polyvinyl alcohol. Celvol MM-14 is a pre-crosslinked polyvinyl alcohol like u> 15 is also Celvol MM-51 but has a higher molecular weight than § Celvol MM-14. Celvol products are Celanese products.

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Celvol products that were not cross-linked were treated with boric acid to effect cross-linking. The treatment was carried out as follows: 300 g of a 15% solution of polyvinyl alcohol was weighed and mixed with 150 g of 3% boric acid.

5 Wet dilatations were measured 5 min after ligation. In spite of the low wet-expansion rates, all samples were bubbling after attachment to the substrate, i.e. the hydrophilic layer alone would not work alone.

Example 3.

Further, the Celvol 103 and Celvol 350 products described in Example 2 were tested with kaolin. The ratio of polyvinyl alcohol to kaolin was 50:50. The polyvinyl alcohol solution contained 10% by weight of 15 boric acid based on the amount of polyvinyl alcohol. Tests were performed on kaolin with different form factor, ND 2591 and so-called. delaminated test pigment with high form factor. The glue was Glutolin '' Normal ', the pH of which was adjusted to> 11.

The combination of Celvol 103 and ND 2591 gave coatings of 12.3 and 16.0 g / m 2 with wet expansions of 0.4-0.6%. The combination of Celvol 350 and delaminated test rabbit at coating rates of 12.2 and 17.4 g / m2 gave wet expansions of 0.3-0.4%.

Also in this case, the samples were bubbling over the substrate after attachment, o

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The invention is not limited to the foregoing, but may vary within the scope of the claims, g 30

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Claims (5)

Wallpaper paper comprising a wood fiber based base paper having a first and a second surface, and a barrier layer on the side of the first surface of the base paper 5, characterized in that the wallpaper paper comprises a hydrophilic layer between the first surface and the barrier layer, or on the surface of the barrier layer, and the hydrophilic layer consists of polyvinyl alcohol and filler, or the hydrophilic layer comprises cross-linked polyvinyl alcohol. Wallpaper paper according to claim 1, characterized in that the barrier layer comprises a barrier layer forming latex, for example styrene acrylate, polyacrylate, styrene butadiene, polyvinyl acetate or ethyl vinyl acetate. Wallpaper paper according to claim 1, characterized in that the hydrophilic layer comprises cross-linked polyvinyl alcohol hydrogel. Wallpaper paper according to claim 1, characterized in that, in addition to cross-linked polyvinyl alcohol hydrogel, the hydrophilic layer comprises filler, preferably kaolin in disk form. 20 Wallpaper paper according to any of the preceding claims, characterized in that the barrier layer comprises filler, preferably kaolin in sheet form. δ (M tn o X Χ CL CO δ sj- o o {M