DE2226746C3 - Process and device for the production of photoprintable, sufficiently UV-permeable paper - Google Patents

Description

50

The production of transparent drawing paper is known from the German Auslegeschrift 12 82 437, wherein a raw paper with a two-component reaction mixture of polyaminoamide resins and epoxy resins are impregnated.

DT-AS 10 09 011 describes a process for the production of waterproof polyester resin coatings on paper by applying a mixture of unsaturated polyester resins containing the usual catalysts and small amounts of paraffin and polymerisation described, which is characterized is that the polymerization is carried out by heating to more than 200 ° C with the proviso, that the hardening time is less than the time it takes for the added paraffin to start to rise the surface of the layer. In the process of the invention, however, no paraffin is used, and the polymerisation takes place at a maximum of 160 "C.

In DT-AS 11 63 774 a process for impregnating or coating flat, in particular absorbent supports with curable prepolymers of diallyl phthalate is described, which is characterized in that the prepolymer or polymer-monomer mixture of diallyl phthalate in the form of aqueous dispersions or Bringing emulsions onto the carrier and drying the carrier at a temperature at which the water evaporates, the prepolymer softens and flows into one another, but not yet fully polymerized. As the example there shows, 150 g / m ⁸ heavy, absorbent soda cellulose paper pigmented in reddish brown with iron oxide is assumed. After the impregnation and hot air treatment, a 400 g / m ² heavy opaque film is obtained, which means that the 150 g / m ² heavy paper has received an impregnation of 250 g / m ^a , so that the known impregnation outside the claimed range of this Invention according to type and amount and the application process. According to Example 2 there is a 40 g / m ^a heavy, non-woven synthetic fiber fleece impregnated, and it is a 80 g / m ² obtained heavy foil. This means that the same amount by weight of synthetic fiber fleece has been impregnated with the same amount by weight of prepolymers of diallyl phthalate. In Example 3 there, ^{cotton liner paper weighing 40 g / m 2 is} impregnated with a prepolymer of diallyl phthalate, so that a ^{film weighing 85 g / m 2} is obtained. In this case 45 g / m ² prepolymer applied to 40 g / m ^a heavy paper.

In TAPPI, 43 (1960), No. 1, Transparentizing of Paper, by Frans V. E. Vau ri o, pp. 18 to 21, is only mentioned in Table 1 on p. 19 approximately in the middle of the page diallylitaconate. With this chemical Use is an unsaturated ester and not an unsaturated polyester, because the diallylitaconate is a monomeric compound. The same statements apply to the diallyl phthalate, which is mentioned on p. 20 in ninth place among the compounds mentioned there and where it is indicated in brackets that it is the monomeric compound.

The other known transparent drawing papers, however, have the disadvantage that, when exposed, they changing relative humidity, in addition to insufficient dimensional stability, a bad one Have UV resistance and dark storage stability and therefore yellow. Furthermore, there is almost always an additional one Surface treatment required to achieve good writability.

The object of the present invention is to provide a method for producing paper that can be photocopied to make available, in which the papers obtained by the process according to the invention are characterized by the following properties at the same time:

a) Showing increased dimensional stability when exposed to changing relative humidity.

b) Showing improved water elongation, measured with the device for fennel. Here the water expansion lies between 0.4 and 0.8%, based on the length, depending on the resin absorption of the clamped strip at one exposure time

of 5 minutes of water. The unsized raw pulp, e.g. B. sulphate pulp or linters,

paper and also the usual base paper made of transparent paper, with which the transparency or

dissolve in water as a result of their poor wet-blueprinting ability, which makes them erasable and

strength after a short exposure time. That reduces the sensitivity to water and moisture

photoprintable paper 5 obtained according to the invention is set.

on the other hand, even when the resin is absorbed by die, it has excellent wet strength due to the impregnation with curable ungell γ. Saturated polyester resin improving the c) having excellent resistance to erasure, transparency and UV permeability, is based on the displacement of the areas erased in the cavities of the paper, as well as trouble-free rewritability. io sensitive air through the auspolymensationsfanige d} exhibiting an excellent yellowing unsaturated polyester resin mixture. The refractive strength Ijei storage in the dark or index is reduced so far that the UV rays having light. Paper becomes transparent and is suitable for blueprints.

mentioned effects. It is already sufficient to use 5 to 15 percent by weight of unsaturated polyester resins, polymerizable unsaturated condensation products (cf. Johan Bjorksten, tes polyester resin, preferably 12 to 17 percent "Polyesters and their Applications", Reinhold pub weight percent. In the well-known Lishing Corporation, New York, 1956, p. 21 to IH) use of curable Epoxyharzmi- understood, the ", ^ - unsaturated dicarboxylic acids are binders in amounts 20 and / or their anhydrides with in the molar Uoervon 47 to 88 percent by weight, based on the polyhydric alcohols used, based on the raw weight of the paper, is required. Polycondensation can be obtained. As a ^"p-B un- saturated dicarboxylic acids are useful, for example:

Geeenstand of the invention is a method of maleic acid, maleic anhydride, Furnar-, itaconic, producing sufficient UV lichtpausfähigem a ₅ citraconic, mesaconic and aconitic acid as well as naioge- ^ .rchlässieem paper by impregnating ned from acids such as Chlormaleinsaure. Combination of unground and ground Part of the «, ^ - unsaturated dicarboxylic acids can

Substance and / or unground and ground thereby in a manner known per se by saturated T interspersed opaque base paper with a dicarboxylic acid, for example o-, iso- and iere-shen weight from about 20 to 200 g / m ", preferably phthalic acid, tetra- and hexahydrophthalic acid Tetra-Sm range from 35 to 100 g / m », with curable chlorophthalic acid, hexachlorendomethylene-gJ-M ^ S resins, characterized in that for phthalic acid, endomethylenetetrahydrophthalic acid.Adi Sen 5 b s 30 percent by weight of an unsaturated pin and sebacic acid and d.merized linseed oil and Polyester resin mixed with alkyl acrylates or soybean oil fatty acid or its anhydrides Alkvlmethacrylaten and possibly another 35 are. "" "" "C ^ pise

Thermosetting compounds, and polyhydric alcohols are preferred

SStiSSStoiai und - accelerator ™ uses dihydric alcohols in question be.spielswe.se A hylen-Ξ and the impregnation in the paper web between glycol, propaned.ol-1,2, butaned.ol-1,3 butanediol-lA room temperature to WTC ^ is polymerized. Diethylene glycol, «P ^^^^ 'SvSS ?.

_{Dk copolymerizable 4} o homologues used for impregnation, neopentyl glycol, ^ ² ' ^A ' ^T L ^im ^ ^h ^ ^nt ^.

Td are determined by the type and amount; - diol-1,3, peatylglycol, oxyalkylated bisphenols hy-

etrt that the refractive index of the third bisphenol, D.methylolcyclohexan._ edoch

^{paper one <s}

ßteMSSSÄriBktenam- = s, get ™ _S Who, jelly · will. ^ Papers can be sesen as transparent ether alcohols in exchange

^b _de papers obtained according to the procedure in place of «^ nOm ^ laÄer. _ü Polyester resins

of the previous character foils, the named art- Jß ^^^^, * ^ A ^ kylacrylate dt can be ΰ ti bil

of the previous characters f_ g Jß ^^^^, ^ A ^ kylacrylate

resins can be used. ΰ »α tvlmethacrvlate use, such as

The result of the impregnation with the unsaturated 6 ₅ or AJkylme hacrylat ^e ™? ™ * ' _n _ _Buty la.cryl _a t,

Polyester resins and the alkyl acrylate hergestel te J ^^^ al ^ AjhyU ^ _Ät ^y _hlrn ^y _eth

The alkyl methacrylates are preferred. The 20 minutes and at elevated temperature (e.g. before

Use of methyl methacrylate belongs to the before 7O ⁰ C) takes about 1 to 2 minutes. It can di <

best embodiment. usual in unsaturated polyester chemistry be

As further vinyl compounds capable of copolymerization, initiators such. B. peroxide compounds with ar

fertilize that can also be used (cf. also known accelerators, use

For example: Bulletin IP 8, July 1961, Amoco Chemicals Insofar as non-yellowing papers are produced

Corporation, titled "The Effect of Resin", may not allow tertiary aromatic amines as:

Ingredients on the Properties of Isophthalic Un accelerators are used,

Saturates Polyesters ", pp. 5 to 19), are, for example. The components of the impregnation solution are allowed to nacr

suitable: styrene, vinyl toluene, p-tert.-butylstyrene, di- io;

vinylbenzene, vinyl acetate, vinyl propionate. As allyl after the solvent has evaporated. There:

Compounds can be used, for example: Diallyl solvent is responsible for the component

phthalate, diallyl maleate, diallyl fumarate, triallyl for the purpose of suitable handling and he ·

cyanurate. The impregnation solutions are rich by adding various specific resin absorbents

usual inhibitors, for example p-benzoquinone, to dilute 15 and thereby the impregnation zi

2,5-Di-tert-butylbenzoquinone, hydroquinone, tert-Bu- improve. It acts as a carrier for the polymerized

catechol, toluyl hydroquinone, and copper-plating components. Depending on the amount of the

compounds such as copper naphthenate, polymerizable mixtures introduced into raw paper;

stabilized in the known amounts, as z. B. results in a more or less good transparency

in the book Kirk-Othmer, Encyclopedia of 20 or UV transmission.

Chemical Technology, Interscience Publishers, New The amount of polymerizable

York, 1969, second edition, Volume 20, pp. 822 to 825, compounds can be diluted accordingly

is described. with volatile organic solvents such as

Suitable preferred polymerization catalysts e.g. B. acetone and methylene chloride are regulated,

are z. B. tert-butyl perbenzoate, dicumyl peroxide, Ben- 25 It has been found that excellent results

zoyl peroxide, lauroyl peroxide, methyl ethyl ketone per- nisse with the addition of 20 to 80, preferably 35 to

oxide, methyl isobutyl ketone peroxide, cyclohexanone peroxide, 60 parts by weight of acetone or methylene chloride,

oxide, azobisisobutyronitrile. measure to 100 parts by weight of unsaturated poly-

Furthermore, the use of ketone peroxides, ester resin, can be achieved.

namely methyl ethyl ketone peroxide, mainly 30 The actual impregnation of the raw paper webs

then recommended. If desired, slightly done, preferably in an immersion bath. Here has

docile discoloration of the hardening products, as it was shown that it is very essential for a perfect

when irradiating, but under certain circumstances also when the paper webs are freely impregnated, is that

Storage, which can occur through exposure to light, to paper first over a back dampening roller

to decrease. 35 and only then leads into the immersion bath. To now air

The usual accelerators, for example inclusions in the paper, which also become one at the same time

Cobalt octoate, cobalt naphthenate, zirconium naphthenate, reduction in transparency or UV-permeable

Dimethylaniline, acetoacetic acid ester, is used. The ability to avoid the infeed takes place

Use of accelerators in the copolymers paper in the immersion bath is best so that it is from the dei

sation of unsaturated polyester resins with a poly- 4 ° rear surface moistening roller made of as pointed as possible

merizable monomers is, for example, in the angled runs into the immersion bath, and so through the

Book Kirk - Othmer, Encyclopedia of Che- backside moistening already given in that

mical Technology, Interscience Publishing, New York, soaking bath from one side to the other

1969, second edition, Volume 20, pp. 825 and 826, tend to be penetrated by the impregnation solution. To

wrote. 45 the passage through the immersion bath, the excess

In connection with the use of ketone shot of impregnation solution between two driven peroxides can be squeezed off press rollers for accelerated hardening or via staggered metal compounds, Stripped like cobalt, zircon and Va-ordered glass rods. The press rolls benadinnaphthenat, or metal chelates, such as cobalt and are either made of surface-hardened steel, Zirconium naphthenate. At the same time 50 other suitable metal alloys or from Presence of peroxides and metal accelerators such as a solvent-resistant plastic however, the storage stability of the impregnation solutions is e.g. B. rubber or polyurethane coated steel. 'or metal core. The nip rollers are used to

The right mixing ratio and the way of achieving a flawless high paper quality

two component system made of unsaturated poly- 55 requirements for concentricity

ester resins and polymerizable compounds to ensure an even application of resin

is to ensure the paper quality and paper thickness as well. The roller suspension must be

the refractive index of the air-free paper must be deduced that the nip depending on the used

agree so that the desired transparency or paper quality concentration and viscosity of the

UV transmission is achieved. 60 impregnation solution can be changed. For the pre

The impregnation solution expediently contains inert organic impregnation with the rear-side moistening roller and

Niche solvents as well as customary polymer for the final impregnation in the immersion bath can

sation initiators and accelerators. The polymeric impregnation solutions are used,

The curing of the impregnated paper takes place

selected so that the curing after evaporation 65 then in a horizontally or vertically arranged

of the solvent at room temperature or the drying tunnel. It can be used both at room temperature

can be carried out at a higher temperature. At as well as at an elevated temperature in the range of

curing at room temperature up to about 160 ^D C, preferably erfoleen at 120 to 140 ⁰ C..

Temperatures higher than 16O ⁰ C should be avoided if possible, since this can lead to discoloration of the P'apiers. When the paper cures at elevated temperatures, hot air is blown in through the air nozzles that are offset in the drying tunnel. Due to the hot air cushion that is created, the paper is now only carried contact-free on the air cushions, fed through the drying channel to the take-off roller and from there to the take-up device. Since the desired polymerization of the polymerizable components occurs in a very short time at the elevated temperature, this procedure is preferred.

The paper produced in this way by the process according to the invention is in the drying tunnel after polymerization immediately with commercially available inks, inks, ballpoint pens, typewriters, pencils and Printing inks can be written on. An additional treatment of the paper surface for better writability is not necessary, as the surface quality that can be achieved already corresponds to the known standard. Furthermore, the paper outperforms erased in terms of its resistance to erasure and rewritability Set all previously known drawing papers in such a way that even after multiple etchings on and trouble-free rewriting is possible at the same point.

Since the impregnation solution used is a reaction of the polymerizable components and not only binding agent obtained by evaporation of the solvent and therefore only with limited processing time of the impregnation approach is to be expected, care must be taken that the Ready-to-use impregnation solution processed quickly after production or through continuous addition new solution is added. The processing time, i.e. H. the time until the reaction starts and the material gels, depending on the choice of polymerization initiators and accelerators, takes from several hours to several months. The processing time is also extended by adding the items already described Solvents like acetone and methylene chloride are essential.

While in the production of known transparent papers by impregnation with a two-component epoxy resin system the additive epoxy resin content with at least 45 weight percent resin absorption, based on the weight of the base paper, Must lie to the required transparency, erasure resistance, dry burst pressure resistance as well Achieving tear propagation resistance is already possible with the transparent paper produced according to the invention with much smaller amounts of polymerizable compounds, since the absorption is more polymerizable Compounds only 10 to 20 percent by weight, preferably 12 to 17 percent by weight, lied to on the weight of the base paper, must be in order to already have all the desired improvements mentioned above are already described.

It should be noted that you have the desired blueprint ability and the required Determine the impregnation and selection of the polymerizable compounds very easily by means of a manual experiment can by impregnating the paper to be impregnated in the manner already explained above and labeled after polymerisation, placed in a tracing device using the usual tracing paper and make a copy. In this way, such impregnation conditions can be determined very quickly that the Test papers on the test blueprint result in a haze-free background.

The preparation of the impregnation solution used according to the invention is illustrated by the following examples.

The impregnation solutions became tracing paper in the procedure already explained above processed.

Unsaturated polyester resin 1

The unsaturated polyester resin 1 used in the examples is a 67 percent strength by weight polyester resin solution in styrene.

The unsaturated polyester is made up of the reaction product

a) maleic anhydride,

b) phthalic anhydride and

c) 1,2-propanediol,
20th

where components a, b and c are present in a molar ratio of 1: 1: 2.1. In the polycondensation until a 67gewichtsprozentige solution of the unsaturated polyester in styrene an acid number was heated for so long, less than 30 exhibited and the viscosity of 1200 to 150OcP, measured at 20 ⁰ C,. The unsaturated polyester was stabilized by adding 200 parts by weight of hydroquinone per million parts by weight to the unsaturated polyester before diluting it with styrene. A 67 weight percent polyester solution was prepared by dissolving the unsaturated polyester in monostyrene. 0.2 percent by weight of a commercially available UV absorber, namely 2- (2'-oxy-5'-methylphenyl) -benzotriazole, was dissolved in the solution.

Unsaturated polyester resin 2

It is the same stabilized unsaturated polyester as specified for the unsaturated polyester resin 1, but the unsaturated polyester is dissolved in a mixture of styrene and methyl methacrylate, the unsaturated polyester content being 52 percent by weight, 26 percent by weight styrene and 22 percent by weight methyl methacrylate Viscosity is 60 to 100 cP at 20 ^° C.

Unsaturated polyester resin 3

The unsaturated polyester resin 3 used in the examples is in the form of a 64 percent strength by weight polyester resin solution in styrene.
The unsaturated polyester is the reaction product

the end

a) maleic anhydride,

b) phthalic anhydride and

c) 1,2-propanediol,

where components a, b and c are present in a molar ratio of 2: 1: 3.15. In the Polykondensatioi was heated for so long until a 64gewichtsprozentig having <solution of the unsaturated polyester in styrene eim acid number of 30 to 33 and the Viskositä 1000-1200 cP, as measured at 2O ⁰ C was. It was stabilized as indicated for the unsaturated polyester resin 1 and a 64 percent by weight solution of the polyester was made with styrene, and the already mentioned UV absorber was dissolved in it in the amount already indicated.

Example 1 curing takes place at an elevated temperature in the area

1000 parts by weight of unsaturated polyester resin 2, ^from 120 to 140 ° C in 2 to 2.5 minutes.

400 parts by weight of acetone. .

30 parts by weight of acetylacetone peroxide (50g example 7

weight percent) and ⁵ 800 parts by weight unsaturated polyester resin 1,

30 parts by weight of cobalt accelerator (1 to 200 parts by weight of butyl acrylate,

percent Co). 400 parts by weight of acetone and

20 parts by weight of tert-butyl perbenzoate.

The processing time of this approach is

Room temperature about 4 to 5 hours. The processing time for this approach is be

curing takes place in the temperature range from 120 to room temperature for about 2 to 3 months. From-

140 ⁰ C in about 2 to 2.5 minutes. hardening takes place at an elevated temperature in the area

Example 2 of 120 to 14O ⁰ C in 2 to 2.5 minutes.

1000 parts by weight of unsaturated polyester resin 2, examples

400 parts by weight of methylene chloride, 800 parts by weight of unsaturated polyester resin 1,

30 parts by weight of acetylacetone peroxide (50-200 parts by weight of butyl acrylate,

weight percent) and 400 parts by weight of methylene chloride and

30 parts by weight of cobalt accelerator (20 parts by weight of tert-butyl perbenzoate.

percent o). _{20 Dig} v _ERAR b _e i _t ungszeit this approach is be

The processing time of this approach is about 2 to 3 months at room temperature. From

Room temperature about 4 to 5 hours. hardening takes place at an elevated temperature in the area

The curing takes place at an elevated temperature of 120 to 14O ⁰ C in 2 to 2.5 minutes.

in the range from 120 to 140 ° C in 2 to 2.5 minutes. _n . . , _n

Example 9

Example 3 _1O qo parts by weight of unsaturated polyester resin 2,

800 parts by weight of unsaturated polyester resin 1, 400 parts by weight of acetone and

200 parts by weight of butyl acrylate, 20 parts by weight of tert-butyl peroctoate.

400 parts by weight of acetone, ~. ... ..

30 parts by weight of acetylacetone peroxide (50g, _{o R} D »e processing time of this approach is be

weight percentage) and ³ ° ^ temperature ^about } ^{bls 3 months} -. ^The , ^from _v

30 parts by weight of cobalt accelerator (1 weight- J * «" "") takes place at an elevated temperature in the reut

percent Co). from 120 to 14O ⁰ C m 2 to 2.5 minutes.

The processing time of this approach is at B e i s ρ i e 1 10

Room temperature 4 to 5 hours. The curing 35 ¹⁰⁰ ° parts by weight unsaturated polyester resin 2,
happens at an elevated temperature in the range of 120 ⁴⁰⁰ parts by weight of methylene chloride and

to 14O ⁰ C in 2 to 2.5 minutes. ²⁰ parts by weight of tert-butyl peroctoate.

_R. ·,. The processing time of this approach is be

Example <t room temperature about 2 to 3 months. The curing

800 parts by weight of unsaturated polyester resin 1, 40 is carried out at elevated temperature in the range of 12C 200 parts by weight butyl acrylate, ⁰ to 14o C in about 2 to 2.5 minutes.

400 parts by weight of methylene chloride,
30 parts by weight of acetylacetone peroxide (50 weight example 11

percent) and ⁸⁰ ° parts by weight of unsaturated polyester resin 1,

30 parts by weight of cobalt accelerator (1 weight- 45 ²⁰ ° parts by weight of butyl acrylate,
percent Co). ⁴⁰ ° parts by weight of acetone and

20 parts by weight of tert-butyl peroctoate.

The processing time of this approach is at The processing time of this approach is at

Room temperature 4 to 5 hours. Curing room temperature about 2 to 3 months The curing uni

happens at an elevated temperature in the range of 120 50 takes place at an elevated temperature in the range of 12C up to 140 ° C in 2 to 2.5 minutes. to 140 ° C in about 2 to 2.5 minutes.

Example 5 Example 12

1000 parts by weight of unsaturated polyester resin 2, ^ 00 parts by weight of unsaturated polyester resin 1,

400 parts by weight of acetone and 55 ²⁰⁰ parts by weight of butyl acrylate,

20 parts by weight of tert-butyl perbenzoate. ^ ^{00 parts by} weight of methylene chloride and

20 parts by weight of tert-butyl peroctoate.

The processing time of this approach is at The processing time is at room temperature

Room temperature about 2 to 3 months. The break for about 2 to 3 months. The curing takes place with him

Curing is carried out at elevated temperature in the range 60 elevated temperature in the range of 120 to 14O ⁰ C ir

from 120 to 140 ° C in 2 to 2.5 minutes. about 2 to 2.5 minutes.

Example 6 examples

1000 parts by weight of unsaturated polyester resin 2, 1000 _{parts by} weight of unsaturated polyester resin 2,

4ÖOGewichtsteieMethylenchloridund ₆₄₀₀ parts by weight acetone, and

20 parts by weight of tert-butyl perbenzoate. ₂ 0 parts by weight of tert-butyl peroctoate.

The processing time of this approach at Raum- The processing time of this approach is at

temperature is about 2 to 3 months. Leave room temperature for about 2 to 3 months. From-

Curing is carried out at elevated temperature in the range of 120 to 140 ⁰ C in 2 to 2.5 minutes.

Example 14

1000 parts by weight of unsaturated polyester resin 2,
400 parts by weight of methylene chloride and
20 parts by weight of tert-butyl peroctoate.

The processing time of this approach is about 2 to 3 months at room temperature. The curing takes place at elevated temperature in the range of 120 to 14O ⁰ C in about 2 to 2.5 minutes.

Example 15

800 parts by weight of unsaturated polyester resin 1,
200 parts by weight of butyl acrylate,
400 parts by weight of acetone and
20 parts by weight of tert-butyl peroctoate.

The processing time of this approach is about 2 to 3 months at room temperature. The curing takes place at an elevated temperature in the range from 120 to 140 ^° C. in about 2 b: 2.5 minutes.

Example 16

800 parts by weight of unsaturated polyester resin 1,
200 parts by weight of butyl acrylate,
400 parts by weight of methylene chloride and
20 parts by weight of tert-butyl peroctoate.

The processing time is at room temperature about 2 to 3 months. The curing takes place at an elevated temperature in the range from 120 to 140 ° C in about 2 to 2.5 minutes.

Example 17

800 parts by weight of unsaturated polyester resin 3,
200 parts by weight of butyl acrylate,
400 parts by weight of acetone and
20 parts by weight of tert-butyl peroctoate.

The processing time at room temperature is about 2 to 3 months. The hardening takes place at higher temperatures Temperature in the range from 120 to 140 ° C in 2 to 2.5 minutes.

Example 18

800 parts by weight of unsaturated polyester resin 3,
200 parts by weight of butyl acrylate,
400 parts by weight of methylene chloride and
20 parts by weight of tert-butyl peroctoate.

The processing time of this approach is about 2 to 3 months at room temperature. The curing takes place at elevated temperature in the range of 120 to 14O ⁰ C in 2 to 2.5 minutes.

The impregnation compound preferably used for the process according to the invention corresponds in each case to the Examples! and 2, 7 and 8, 13 and 14, the differences in the approaches in each case in the solvent and are in the polymerization initiators.

The following are the mechanical values that can be achieved in the case of products manufactured according to the invention Transparent papers with a resin absorption in the paper of 11, 14, 17 and 20 percent by weight in the Table reproduced in summary.

Resin absorption
in paper
(%) Water expansion
after
fennel
(%) Dry burst
reprint
Mullen
(kp / cm ') Wide white
strength
after
Kimendorf
(G) Eraser
strength Writability
A ink, B Indian ink, C ball
scribe, D pencil,
E typewriter,
F printing ink without impregnation
11th
14th
17th
20th 0.8
0.8
0.6
0.4 1.02
1.45
1.68
1.72
1.76 37
46
54
58
60 Well
very good
very good
very good
very good A + B runs out, C, D, E, F a lot
Well
A-fB good, C, D, E, F very good
A, B, C, D, E, F very good
A, B, C, D, E, F very good
A, B. C, D, E, F very good

The values listed above are achieved when the paper according to Examples 1, 2, 7, 8, 13 and 14 is soaked.

The drawing schematically shows a system that can be used for the production of the transparent paper shown. The system works in the following way: The paper web is passed over the numbers 1 and 6 designated motor-driven take-off rollers transported through the system. These take-off rollers are in the running speed continuously controllable. From the take-off roller 1 is the paper to be impregnated Guided over a deflection roller on the back moistening roller 2. Here there is a pre-soaking, which is necessary for perfect impregnation of the paper in the immersion bath. The drinking trough 3 must be continuously fed with new impregnation solution according to the paper flow; achieved thereby one has a uniform impregnation viscosity and a uniform paper quality. After the run by the immersion bath in the soaking tub 3, the excess of soaking solution between two press rollers4 squeezed. The impregnated paper is then fed into the drying tunnel. Located in the drying tunnel the hot air supply 5, which consists of a nozzle system. It comes from the increase in temperature then for the polymerization of the impregnation solution in the drying tunnel. After it has passed through the drying tunnel, the impregnated and hardened paper is overturned the take-off roller 6 and via a folding roller dei on winding device 8 supplied. Here is the Transparent paper either through cooled take-off rollers 6 or through a cold air supply 7 aul Room temperature cooled. After this operation, the transparent paper produced according to the invention stands available as a usable paper web.

1 sheet of drawings

Claims (7)

Patent claims: 1. A method for producing photoprintable, sufficiently UV-permeable paper by impregnating opaque base paper produced from combinations of unground and ground pulp and / or unground and ground linters with a basis weight of about 20 to 200 g / m: ² , preferably in the range from 35 to 100 g / m ² , with curable synthetic resins, characterized in that 5 to 30 percent by weight of an unsaturated polyether resin mixed with alkyl acrylates or alkyl methacrylates and optionally other polymerizable compounds and polymerization initiators and accelerators is used for the impregnation, and the impregnation is copolymerized in the paper web between room temperature to 160 ⁰ C. 2. The method according to claim 1, characterized in that the alkyl methacrylate is methyl methacrylate is used. 3. The method according to claim 2, characterized in that that styrene is used as a further copolymerizable compound. 4. The method according to any one of claims 1 to 3, characterized in that the impregnating agent with a content of volatile organic solvents is used. 5. The method according to any one of claims 1 to 4, characterized in that the paper web is first pre-soaked via a rear-side dampening roller and then passed through an immersion bath will. , 6. The method according to any one of claims 1 to 5, characterized in that the paper with 10 to 20 percent by weight, preferably 12 to 17 percent by weight, impregnated polymerizable compounds will. 7. Device for performing the method according to one of claims 1 to 6, characterized characterized that these take-off rollers, deflection rollers, rear-side dampening rollers, an impregnation system, includes a squeegee system, a drying tunnel and a winder.