DE3315517C2 - Transparent intermediate original sheet - Google Patents

Abstract

Transparent intermediate original sheet made from a base material which, by impregnation with a transparency agent, contains 1) a polyether polyol with two to eight terminal hydroxyl groups, 2) an alkanolamine resin, 3) a diisocyanate or polyixocyanate and 4) sucrose acetate isobutyrate, and then polymerization curing of the transparency agent has been made. If necessary, a second layer can be applied to the base material treated in this way, which layer contains at least one formaldehyde scavenger and a binding agent.

Description

and that the intermediate master sheet has a second layer which is a formaldehyde scavenger, a binder and contains a wetting agent.

The invention relates to a transparent intermediate original sheet which is used as a drawing sheet or as an original which can be reproduced by diazotype. The Zwlschenoriginalbllder can then by labeling, e.g. B. with pencil, or by conventional copying processes, z. B. by diazo type, silver halide photograph or an electrophotographic copying method.

Intermediate original sheets for the fields of application mentioned should generally have the following properties exhibit:

(1) high transparency; (2) high paper strength, i.e. tensile strength, crease resistance and tear strength, (3) no cracking in folding; (4) high dimensional stability with no curling or curling; (5) easy correction, Completing and cycling from original images; (6) Maintaining the required transparency during storage without discoloration, e.g. B. Gilben.

In addition, in the case of Zwlschenorlglnalblätter on which original images are generated with normal paper copiers the following requirements are made:

1) Good toner absorbency;

2) easy tapering or complete removal of toner images without haze with a retouching agent;

3) No odor nuisance;
4) heat resistance;

5) smooth transport through the copier without double feed, paper jam, or the like;

6) does not affect the charging of the photoconductor of the copying machine and

7) no contamination of the copier's fixler rollers.

Conventional intermediate original sheets can be divided into the following four categories:

Group a

Tracing papers made from natural cellulose fibers in the form of a thick pulp suspension or corresponding papers that have also been treated with polymeric substances;

Group B

Papers that you impregnate tracing papers that are more opaque than those of group A, with oils, We'chmachern, liquid paraffins or the like. Obtained;

Group C
Plastic films with various surface treatments;

Group D

Bo η. which have been made transparent by heat treatment of papers from a mixture of synthetic pulps based on thermoplastic synthetic resins and natural cellulose pulps.
However, none of these types has proven to be satisfactory in terms of the combination of the above requirements.

Group A intermediate master sheets are the most widely used. However, they are strongly subject to this Influence of moisture so that they roll easily, curl and have poor dimensional stability. Further

they show poor water resistance and low paper strength.

Group B intermediate original sheets show better dimensional stability and water resistance than that Group A leaves, however, migration of the transparencies occurs during prolonged storage or when exposed to heat in a copier, blurring the original images. Besides, they are generally less writable and less transparent than the materials of group A and break easy to fold or crease.

The group C intermediate original sheets made of plastic rolls are superior in transparency and dimensional stability, but they are difficult to write on with pencil and ink. They also take Coating fluids do not respond well and are relatively expensive.

The Group D intermediate standard sheets also show excellent dimensional stability, but contain Due to the heterogeneous distribution of the synthetic and natural pulp, they always have opaque spots, the cause uneven transparency. The sheets are also difficult to write on and are expensive.

Paper is a fiber material with many voids between the fibers that scatter incident light. A known physical method of making paper transparent is to remove the spaces between to fill the fibers with a translucent having an identical or very similar index of refraction like the paper fiber did. If a low-melting liquid or solid material is used as a transparent agent, in particular, the problems mentioned above for Group B blades arise. On the other hand, if a polymer material having a high melting point is used as a transparency. so can this does not penetrate completely into the paper, and a good and homogeneous transparency finish can be achieved difficult to achieve.

Relatively low molecular weight materials are currently being investigated as transparency agents which by treating with a catalyst, heat or UV light after penetrating into the base paper can be hardened. Materials of this type are e.g. B. reactive resins, oligomers and monomeric substances, in particular thermosetting resins, such as phenolic resins, urea resins, melamine resins and / or alkyd resins.

The heat curing of these Transparentlermluel is slow and although it is by increasing the Curing temperature or the addition of an acidic catalyst can be increased somewhat, is neither preferred because the base material is attacked. In addition, are made of these thermosetting resins Sheets are stiff, have poor paper strength, tear easily and develop unpleasant odors Heat.

In JP-OS 52 46 113 another process is described in which an oligomer with an isocyanate group is used as a transparency. JP-AS 51 36 367 describes the use of a polyisocyanate in combination with a polyester polyol as a transparent agent. In both cases, however, arises with slight heating. In the paper a polymer, e.g. B. a polyurethane, and by these methods obtained sheets yellow easily and absorb moisture so that they curl. Such sheets are for Plain paper copiers are not suitable.

JP-OS 48 98 111 discloses a transparent agent in the form of a mixture of an etherified amniotic resin and sucrose acetate isobutyrate are known. Intermediate original sheets made transparent with this means are due to their poor paper strength, especially poor tensile strength, not for plain paper copiers usable and develop unpleasant smells when heated slightly.

From DE-AS 12 14 989 a transparent agent is known, which is a polyisocyanate and a polyether triol contains. Since the polymerization of these components already takes place at room temperature, the pot life of the Use transparent mediums that are extremely short and thus transparent intermediate original sheets a dirty yellow hue. In addition, the transparent film has hygroscopic properties, see above that so made transparent Materlallen wave at high temperatures and z. B. for transmission of toner images are unsuitable.

In GB-PS 10 12 120 is a method for transparent paper and paper products or for The creation of watermarks in these products is described by applying a liquid to the paper Treated solution containing sucrose acetate butyrate or isobutyrate. When using transparent agents, which contain sucrose acetate isobutyrate as a main component, however, can only have a limited transparency because the treated material is not sufficiently impregnated with the resin. Also form when folding the material made transparent white fold lines and this is also not with aqueous Inks can be written on, as the transparency agent has hydrophobic properties.

The object of the invention is therefore to provide a transparent Zwlschenoriglnalblatt with a improved transparency agent has been impregnated and, in addition to high transparency, high paper strength, improved resistance to breakage when wrinkled and excellent dimensional stability as well Has resistance to rolling and curling, can be easily corrected, erased, supplemented and printed, for copier machines, z. B. plain paper copier, is suitable and does not develop any unpleasant odors.

The invention relates to a transparent Zwlschenoriglnalblatt made of a base material that with is impregnated with a polymeric transparency made from a polyether polyol and a polyisocyanate and which is characterized in that the transparent agent

1) based on 100 parts by weight of a product obtained by the addition reaction of propylene oxide and / or ethylene oxide Polyether polyols with 2 to 8 terminal hydroxyl groups,

2) 20 to 100 parts by weight of an alkanolamine resin,

3) 2 to 50 parts by weight of a diisocyanate or polyisocyanate and <>?

4) contains 10 to 60 parts by weight of sucrose acetate isobutyrate and that the intermediate original blue has a second layer which contains a formaldehyde scavenger, a binder and a wetting agent.

The first component, i.e. H. the polyether polyol obtained by the addition reaction of propylene oxide or ethylene oxide is obtained alone or in combination, forms a linear or by reaction with the isocyanate cross-linked polyurethane and additionally a polymer with a network structure through reaction with the alkanolamine resin. Any polyether polyol derivatives can be used as starting materials for Manufacture of urethane resins are used. Examples of polyether polyols with 2 to S hydroxyl groups at the ends of the molecule are polyethylene glycol, polypropylene? lycol, polyethylene-polypropylene glycol and polyols, the addition reaction of ethylene oxide or propylene oxide with glycerol, trimethylolpropane, pentaerythritol, Sucrose or ar-methyl glycoside can be obtained. Aromatic polyphenols, such as bisphenol A, can also used turn. These polyether polyols are appropriately selected, at least the following

ίο both factors (i) and (ii) should be considered: (i) the co-solubility with an applied Solvents that depend on (a) the structure of each polyol; H. the type of monomeric three-ring compound known as Starting material for the production of the polyol by ring-opening polymerization of the monomeric compound is used, and (b) depends on the degree of polymerization, and (ii) the flexibility of the reaction of the Polyol with the diisocyanate or polyisocyanate (3) resulting urethane polymer.

Examples of the alkanolamine resins used as the second component are urea resins, melamine resins, Guanamine resins and the like alone or in combination. For the production of modified alkanol resins you can lower alcohols such as methanol to higher alcohols such as octanol can be used. With regard improved penetration into the paper, hardening properties, stability, co-solubility, flexibility, strength, Moisture resistance and economy are, however, alcohols with 3 to 5 carbon atoms for the Modification of the alkanol resins is preferred.

The methylol and ether group content of the amine resins is in a range that does not pose a problem which induces co-solubility, hardening and stability. Preferred areas are:

for melamine resins: 3 to 5 methylol groups and 1 to 3 ether groups per melamine group;

for urea and

Guanaminhsrzc: 1 to 3 methyl groups and 0.5 to 2 ether groups per urea or guanamine

group.

In view of the penetration into the paper, the molecular weight is preferably less than 1,000.

According to the invention, amine resins are used not only because they are thermosetting Resins such as phenolic resins, epoxy resins and unsaturated polyester resins have superior curing properties and have stability so that the sheets can be made transparent more easily, but also due to their low coloring, good weathering and yellowing resistance as well as high transparency towards near Ultraviolet light. By properly choosing the composition of the amine resin and its blending ratio With the polyether polyol, highly flexible to rigid materials can be obtained, depending on requirements. However the mixing ratio must be kept within a certain range as explained below is used to prevent blocking and migration of the transparency after curing and spreading of the To prevent original images and to increase the solvent resistance, paper strength and writability to enhance.

As a third component, i. H. as a diisocyanate or polyisocyanate, are, for. B. diisocyanates, such as tolylene diisocyanate. Diphenylmethane ^^ '- isocyanate, naphthylene diisocyanate, toluidine diisocyanate, hexamethylene diisocyanate, Isophorone diisocyanate. Dlcyclohexyldilsocyanat, xylylendlisocyanal and Lysindilsocyanat alone or in Combination. In terms of toxicity and durability, however, they are commercially available polyol adducts of diisocyanates as well as commercially available diisocyanate polymers are preferred. Block isocyanates, as adducts when using compounds with active hydrogen, such as phenol, primary Alcohols or caprolactam, can be used. To limit the yellowing, hexamethylene isocyanate. Xylylene diisocyanate or its polymers can be used selectively.

Aliphatic diisocyanates are generally less reactive than aromatic diisocyanates and should be be taken into account when selecting the connections. Especially in systems where an acidic catalyst is applied, the viscosity when using an aromatic polyisocyanate can be dependent Increase on the amount of acid catalyst added, and the sheet may be unusable because of it color formation occurs due to the formation of complexes.

As the fourth component, i. H. as sucrose acetate isobutyrate. can e.g. B. one having a molecular weight from 832 to 856 and a boiling point of 288 ° C can be used.

The amount of the second depends on the mixing ratios of the components described Component according to the intended use of the intermediate original sheet and the type of transparency. Usually, however, more than 20, preferably more than 25, weight points and less than 100 are used Parts by weight per 100 parts by weight of the first component (polyether polyol). When using the second Component in an amount less than 20 parts by weight If the curing reaction is not complete by itself if the amount of the acidic catalyst is increased, which leads to a migration of the transparency agent and leads to lower solvent resistance. A higher proportion of the second component results in a stiff and solid intermediate original sheet. In a slightly higher range (about 30 to 40 weight points), improvements are made Achieved properties in terms of breaking when wrinkling as well as curling and curling. Will however If the second component is used in an amount of more than 100%, the resulting intermediate sheet will tear easily and there is an odor that cannot be tolerated for normal paper copiers is.

The proportion of the third component (diisocyanate or polyisocyanate) is 2 or more parts by weight, preferably more than 5 parts by weight, and not more than 50 parts by weight per 100 parts by weight of the first

Component (polyether polyol). The addition of the third component has the following effects:

a) Better absorption of water-soluble ink, helmet labeling and printing as well as better drying;

b) Knltterproof;

c) Higher paper strength, especially against creasing, pulling and breakage, as well as improved strength the heating and shelf life;

d) improved, gloss-free appearance of the transparent b!?. ues.

Transparencies containing the third component thus show excellent properties in the Compared to those that only contain the first and second components. If the third component is in a Amount of less than 2 weight points is used, the effects mentioned cannot be achieved. On the other hand, if more than 50 parts by weight is used, the polymerization of the active isocyanate groups will occur promoted by the acid catalyst, reducing the shelf life of the liquid due to foaming and high viscosity is adversely affected. It is then not only difficult to manufacture in more stable Way to perform, but the obtained Zwlschenorlglnalblatt also tends to curl, so that the feed becomes difficult during copying. Such an intermediate original sheet cannot be used in standard paper copiers can be used.

The fourth component (sucrose acetate isobutyrate) is used in an amount of 10 to 60 parts by weight per 100 Weight point of the first component (polyether polyol) used. If less than 10 weight points are used, so the sheet obtained has insufficient paper strength, e.g. B. Tear, crease and break resistance, and, as in the case of the polyether polyol, sets aggressive during the cleaning process in a plain paper copier Odors free. An amount of sucrose acetate isobutyrate of more than 60 weight points has a negative effect on the feeding of the intermediate sheet in normal paper copiers due to the relatively high viscosity of sucrose acetate. Furthermore, sucrose acetate isobutyrate penetrates paper less well than polyols and alkanolamine resins, so that it can remain on the surface after impregnation. Such leaves are very shiny and are difficult or impossible to write on or can be retouched with water-soluble ink, as the ink is caused by the Sucrose acetate remaining on the surface of the intermediate leaf is repelled.

The conditions of the curing reaction between the three components depend on the particular formulation of the transparency agent, the amount of the acidic catalyst and the drying and heat treatment conditions after the application of the transparency agent to the base material. In contrast to conventional transparencies, however, strict curing conditions are generally not necessary. If a sufficient maximum I- to 2minütlges heating to 12O ⁰ C or an equivalent heat treatment. There is therefore no risk of damage to the base material. In addition, the use of the first component allows curing to be carried out at room temperature for 1 to 5 days if an optimal ratio of acid catalyst and transparency agent is chosen.

Examples of acidic catalysts are p-toluene sulfonic acid and monobutyl phosphate. Carboxylic acid esters, such as Di-methyl oxalate, and acid anhydrides such as maleic and phthalic anhydrides. These acidic catalysts can be applied to the base material beforehand, but they are preferably in combination with the transparent material contained in a solvent and are then applied to the base material. The amount of acid catalyst depends on the solvent chosen. Using of polar solvents such as water or alcohols, the amount of catalyst is preferably about 10 up to 35 parts by weight per 100 parts by weight of the first component. When using non-polar solvents, z. B. aromatic hydrocarbons, the preferred amount is about 7 to 25 parts by weight per 100 parts by weight of the first component. If the curing is incomplete, the translucent migrates. which not only affects the image quality by distributing the images, but also a Causing blobs of the water-soluble ink. It is therefore necessary to effect a complete hardening. If the amount of the acidic catalyst is below the stated range, it is not complete Hardening, unless a hardening temperature of more than 150 ° C is used. At temperatures of however, above 150 ° C, the strength of the base material decreases considerably. If you use the sour If the amount of catalyst used is above the stated range, the stability of the transparency agent decreases and the intermediate original sheet becomes brittle and yellowed due to the excess catalyst after application to the base material, which affects the durability v. '! rd.

As the organic solvent, any solvent that dissolves the translucent can be used alone or can be used in combination, e.g. B. ketones such as methyl ethyl ketone and methyl isobutyl ketone, and aromatic Hydrocarbons such as benzene or toluene. In particular in the case of the transparency agent according to the invention it has been shown that the polarity of the solvent has a great influence on the strength of the paper Surface gloss and changes in the viscosity of the transparency solution over time. Using of polar solvents, such as alcohols, is the temporary change in the viscosity of the transparency agent liquid is low, and the liquid is more stable than in the case of aromatic hydrocarbons, such as Toluene and ketones such as methyl isobutyl ketone, although the former have active groups reactive with isocyanate groups contain. The intermediate seriginaiblait obtained in the former case, however, shows in comparison to the latter Fall on a lower paper strength, in particular tear strength and breaking strength. Dries In addition, if you use the former to harden it with a dryer, the surface becomes shiny, which not only makes it the appearance is impaired, but also problems with labeling with water-soluble ones Inks and seals with water-soluble stamp inks.

When using non-polar solvents such as toluene, the change in viscosity over time is indeed of the transparentizing agent is somewhat larger than in the case of alcohols, but the difference is for practical purposes Application not significant, and the sheet obtained shows excellent paper strength and surface

shiny. When using ketones, such as methyl isobutyl ketone, properties are between those of Alcohols and aromatic hydrocarbons achieved. It is therefore useful as a solvent for Dissolve all components of the transparency agent in a mixture of polar and non-polar solvents to choose a suitable ratio.

When mixing the transparency agent is preferably z. B. the following order applied since a Isocyanate and an acidic catalyst are present. First the first component (polyether polyol) and the second component (alkanolamine resin) mixed with the solvent, whereupon the acidic catalyst is added and after stirring the third component (isocyanate) is added. The fourth component (sucrose acetate isobutyrate) can be added at any stage. Mixing the isocyanate and the

ίο acidic catalyst directly, this quickly creates gel deposits. On the other hand, there is the acidic catalyst and the isocyanate to the first component (polyether polyol) prior to mixing with the second component (Alkanolamine resin). so an abrupt exothermic reaction sets in. It is therefore preferable to ask firstly a mixture of polyether polyol, alkanolamine resin, sucrose acetate isobutyrate and solvent and then slowly adding the acidic catalyst and isocyanate with stirring.

Together with the components mentioned, excipients such. B. plasticizers, permeating agents, antistatic agents, fillers, coloring agents and lubricants can be used. In addition, after the transparency finish, a second resin coating can be applied to one or both sides of the intermediate original sheet.
Suitable basic materials are, for. B. paper, fabric, nonwovens and other conventional materials.

Quality paper with a basis weight of 20 to 100 g / m ^{2 is} preferred.

The application of the transparent agent to the base material can, for. B. by dip-squeeze coating, Air brush, glass squeegee, wire rod and roller coating are carried out. To remove the With the solution, it is sufficient to dry with cold air or warm air of 50 ° C or below, and it is no need to heat the material to high temperatures.

The amount of the translucent should be chosen to be about 5 to 80%, preferably about 10 to 50% of the base material after drying. When drying with warm air of more than 50 ° C the hardening takes place too fast for a completely homogeneous penetration of the transparentizing agent In the base material, and the surface of the intermediate original sheet obtained is therefore strong glossy, so that pencil and ink writability and transparency are impaired. in the in general, after drying, the material is ripened at room temperature in order to fully cure to effect. Curing can be done simply by adding the transparency agent and the acidic Leaves catalyst for 1 to 5 days. However, it is usually sufficient to keep 1 to 2 minutes at 120 ° C or less to heat with HlITa of the dryer of a loading device or a suitable heat source or carry out an equivalent heat treatment. When hardening under the application of pressure, one obtains a Intermediate original sheet of excellent transparency.

A supercalendering treatment can also be carried out after hardening.

The transparency agent according to the invention contains materials of relatively low molecular weight which allow good penetration into the base material and make it uniformly transparent. In addition, it gives the appearance of tracing paper without a glossy surface, as is the case with conventional materials. After curing of the translucent E there are no problems with the migration and distribution of the original folder and the intermediate sheet made transparent with the transparent agent according to the invention shows advantages in terms of dimensional stability, heat-resistant wedge, correctability of toner images, high paper strength and the absence of cloudiness on folds.
Due to the presence of an alkanolamine resin as the second component, some odor may arise from released formaldehyde. In addition, although the curing gives an excellently transparent base material with good lightfastness and dimensional stability, it may be desirable to improve the writability with pencil and ink or Indian ink, especially water-soluble ink and conventional marking inks, and to increase the drying speed of these inks. In this regard, it has been found that the stated objectives can be achieved if, after the transparency described above, a second layer of a formaldehyde scavenger, a binding agent and a wetting agent is applied to the surface of the intermediate original sheet.

Organic compounds containing amino groups, such as urea and are suitable as formaldehyde scavengers Thiourea, as well as inorganic compounds such as sodium sulfite. The formaldehyde scavenger is used to keep the In the free formaldehyde contained in the alkanolamine resin and thereby the unpleasant formaldehyde odor particularly in the image fixing stage of plain paper copiers.

Suitable binders are, for. B. the following known compounds: water-soluble polymer materials, such as starch, gelatin, polyvinyl alcohol (PVA) and cellulose derivatives such as ethyl cellulose, cellulose acetate isobutyrate and carboxymethyl cellulose. Acrylic and vinyl resins, which are relatively strong, can also be used Make films.

The use of the water-soluble resins mentioned has the purpose, in particular the absorption capacity for water soluble inks to increase. In the case of PVA, it is known that the solubility In cold and hot water, the viscosity of the aqueous solution, the film strength, film elasticity, water resistance as well as solvent resistance influenced by the degree of polymerization and degree of solubilization. When choosing the Materials should therefore take these factors into account.

(ö In addition, a thermosetting resin can be used. Suitable thermosetting resins are, for example, copolymers of (a) ethylenically unsaturated monomers containing a reactive functional group, and (b) one or more acrylic or other vinyl monomers which do not have such a reactive functional group exhibit.

Ethylenically unsaturated monomers which contain a reactive functional group are e.g. B. Monomers with carboxyl groups such as acrylic and methacrylic acid, monomers with epoxy groups such as glycidyl acrylate and methacrylate. Monomers with amino groups such as acrylamide and methacrylamide, compounds with methylol groups or alkylmethylol groups, such as methylolacrylamide, and monomers with hydroxyl groups, such as Hydroxyalkyl acrylate.

Acrylic or other vinyl monomers that do not have a reactive functional group are, for. B. Methyl acrylate, ethyl acrylate, butyl acrylate, methyl methacrylate, vinyl chloride and vinyl acetate.

Copolymers containing the functional monomers mentioned are, for. B. selche with self-bridging Properties and those with a hardener, e.g. B. an amine resin, epoxy resin or isocyanate resin, be bridged. Resins of the self-bridging type are e.g. B. in the case of emulsion systems, acrylic resins, such as styrene-ethyl acrylate-methylolacrylamide copolymers, styrene-butyl acrylate-methylolamine copolymers and denatured styrene-butadiene copolymers.

Resins of the self-crosslinking type are e.g. B. In the case of solvent systems, polymers formed by intermolecular crosslinking, with metals such as zinc, iron, nickel, Κλ ^ λ ¹ 'copper. Calcium. Barium, manganese, aluminum, lithium or sodium, can be introduced into the aforementioned functional ^ · Monorrere. The self-crosslinking resins show excellent oil resistance and are not attacked by organic solvents, so that they improve retouchability.

Various conventional cationic, anionic or non-ionogenic surfactants can be used as wetting agents be used. The following wetting agents are particularly suitable. The use of these wetting agents Its purpose is that, owing to its hydrophilic properties, it can be wetted with water-soluble Improve inks, favor the trapping of formaldehyde, as the formaldehyde scavenger when the wetting agent is added more easily penetrates into the base material, and an even application of a second layer on the Surface of the transparent intermediate original by reducing the surface tension of the coating solution to less than 0.04 N / m, preferably 0.02 to 0.03 N / m, if a water-soluble or emulsion type coating liquid is applied.

However, conventional surfactants are not used because of side effects, e.g. B. low water resistance and Foam development, generally not preferred. However, intensive studies have been carried out on wetting agents showed that tertiary alcohols with an intramolecular acetylene bond and non-ionic surfactants from tertiary alcohol-ethylene oxide adduct type are particularly suitable. They show excellent miscibility with Binders, good anti-foaming properties and give clear results when copied with a plain paper copier Pictures.

When used in aqueous systems, the surfactants mentioned are within their solubility limit used.

Characteristic properties that occur when using non-ionic surfactants in the form of tertiary Alcohols with an acetylene bond or tertiary alcohol-ethylene oxide adducts are reduced Viscosity, more stable viscosity and significant anti-foaming effect during the manufacture of the intermediate original sheet. The electrical resistance is reduced in the finished intermediate original pages, there is no Decrease in image density or white stain, and at high humidity there is no deterioration in Observe fixability of toner images.

The wetting agents that can be used according to the invention are not restricted to the above-mentioned materials limited, but it can be, for. B. also non-ionic surfactants from ester, ether, alkylphenols sorbitan ester, Polyoxyethylene sorbitan ester and silicone glycol copolymer types, anionic surfactants from fatty acid selfen and alkyl sulfate type and amine salt, methyl and benzyl type cationic surfactants are used will. Type and amount should be co-soluble with the binder in terms of permeability. Stability, Foaming properties and harmful effects of residual surfactants can be selected appropriately.

With regard to the application amount of each of the above components, the amount of the formaldehyde scavenger depends on the kind of the alkanolamine resin and the formulation, but is usually more than 0.5 g / m ² and preferably about 1.0-3.0 g / m ² . If larger amounts are used, the transparency of the intermediate original sheet is reduced, as if urea is used, it turns yellow if stored for a long time and the paper becomes brittle. The minimum amount required should therefore be used.

In the case of the binders, more than about 0.1 g / m ¹ , preferably more than about 0.3 g / m ² , is generally sufficient.

The wetting agents are usually about 0.1 to 0.3 parts by weight per 100 parts by weight of the solvent applied. The minimum amount should take into account the type of wetting agent, its distribution and Permeability can be determined while the maximum amount In terms of water resistance, stickiness and the consistency is right.

The components mentioned are dispersed in a solvent capable of dissolving them and then applied to the surface of the base material. Suitable solvents are, for. B. water, alcohols, Ketones, esters and aromatic hydrocarbons individually or in combination. Furthermore, according to the invention if appropriate, conventional excipients can be used, e.g. B. fillers, lubricants, colorants and Antifoam agents.

The secondary coating is applied by conventional methods, e.g. B. by reversing roller, Engraving, air brush and wire rod coating. Drying can be done quickly in a dryer.

The obtained intermediate original sheet has excellent dimensional stability, water resistance, printability, Radlerbarkelt, Tonerblld fixability, retouchability and writability and is excellent for Suitable for drawing, drafting and copying. Especially as an intermediate original sheet for plain paper copiers.

The following examples illustrate the invention. All parts are based on weight unless otherwise is specified.

example 1

A combination pulp of 20 parts of coniferous wood pulp and 80 parts of deciduous pulp is comminuted to a freeness (Canadian standard) of 350 cm ^s and on conventional catfish to a paper sheet with a basis weight of 55 g / m ^! processed. This base paper is impregnated with the following transparency agent. After wiping off excess transparency with a wire rod, drying is carried out for 2 minutes at 40 ° C. and rolling is carried out.

Transparent parts

First component: Polyether triol of polyethylene oxide adduct type 90

Second component: hexamethoxymethylolmelamine 40

Third component: diisocyanate polymer (solid content 75%) 10

Fourth component: sucrose acetate isobutyrate (Fesigehail 90%) 20

Catalyst: p-toluenesulfonic acid (solids content 60%) 12

J ₀ solvent: xylene 50

Methanol 40

The impregnated paper is ripened for 2 days and then heated to 120 ° C. for 2 minutes. The resulting intermediate sheet, impregnated with the transparency in an amount of 17 g / m ^2, has an opacity of 35%, a folding resistance wedge MD of more than 1000 ×, a breaking resistance of 3.53 105 Pa, a tensile strength CD of 36 × 10 -4 ³ N and exhibits excellent dimensional stability, toner image retouchability and crease resistance. These properties are determined according to the following Japanese standards: opacity (JIS P 8138), crease resistance (JIS P 8115), fracture resistance (JIS P 8112) and tensile strength (JIS P 8116).

Then the following second accelerating liquid is applied to both sides of the base paper with a wire rod. By drying the paper in a dryer, an intermediate original sheet No. 1 according to the invention is obtained with a second coating in an amount of 1.8 g / m ² .

Second coating liquid parts

Urea 6

Polyvinyl alcohol 2

Surfactant based on a part. Alcohol with acetylene bond 0.2

Water 80

The obtained intermediate original sheet No. 1 shows excellent dimensional stability, toner image retouchability and FaIz haze resistance. Its absorption capacity for water-soluble inks is excellent, stamp marks are very clear and there is practically no odor when copying in a plain paper copier.

Example 2

The base paper used in Example 1 is mixed with the following transparent agent (solids content 50%) impregnated:

Transparent parts

First component: Polyether diol of polyethylene oxide adduct type 90

Second component: methyl-ethyl-alkylated methylolmelamine 40

Third component: diisocyanate-polyol adducts 12

Fourth component: sucrose acetate isobutyrate 10

Catalyst: p-toluenesulfonic acid 15

Toluene 90

The dry application rate of the translucent is 16 g / m ² . After standing for 2 days and nights, the original sheet obtained is heated to 120 ° C. for 1 minute.

Subsequently, the following second coating liquid is applied to the surface of the obtained intermediate original sheet with an air brush, and then dried to obtain an intermediate original sheet No. 2 of the present invention having a dry coating amount of the second layer of 2.2 g / m ² .

Second coating liquid parts

Thiourea 8

Strength 3

Modified styrene-butadiene copolymer 5

tert. Alcohol-ethylene oxide adduct 0.3

Water 100

The intermediate original sheet obtained shows similar properties to the sheet of Example 1. When made toner images with a plain paper copier are found to have excellent toner pick-up.

Example 3

On the surface of a base material made transparent with the transparency agent of Example 2, the following second coating solution is applied with a wire rod and then dried to obtain an intermediate original sheet according to the invention with an application rate of 1.5 g / m ² .

Second coating liquid parts ²⁰ '

Urea 5

Vinyl copolymer 3

Surfactant based on a tert. Alcohol with acetylene bond 0.2

Methyl cellosolve 80

The obtained intermediate original sheet No. 3 shows similar properties as the sheet No. 1 of Example 1. At the production of toner images with a plain paper copier provides excellent toner uptake J ° established. When the humidity is high, there is no decrease in image density or bleaching and the intermediate original sheet shows excellent toner image fixability.

B e i s ρ I e 1 4 JS

The base material of Example 1 is impregnated with the following transparency (solids content 50%):

Transparency means parts

First component: polyether diol from polyethylene oxide adduct / ethylene

oxide adduct type 90

Second component: methyl-ethyl-alkylated benzoguanamine resin 45 _4J

Third component: diisocyanate polymer 10

Fourth component: sueroxacetatiosbutyrate 20

Catalyst: p-toluenesulfonic acid 15

Ethanol 100

The transparency agent is applied in an application amount of 16 g / m ² . The base paper made transparent is left to stand at room temperature for 2 days and nights and then heated to 130 ° C. for 1 minute.

The following second coating liquid is then applied to the surface of the base paper with a wire rod and, after drying, an intermediate sheet No. according to the invention is obtained with a dry application rate of the second coating liquid of 1.6 g / m ² .

Second coating liquid parts

Urea 6

Polyvinyl alcohol 2

Acrylic copolymer 3

Silicone 0.1

Water 80

The obtained intermediate original sheet No. 4 is, as in the case of Example 1, suitable for practical use. In the Production of toner images with a normal paper copier becomes excellent and smooth Detected toner absorption.

10

Claims (2)

Patent claim: Transparent intermediate original sheet made from a base material which is impregnated with a polymeric transparency agent made from a polyether polyol and a polyisocyanate, characterized. B that the transparency means ■ 1) based on 100 parts by weight of an addition reaction of propylene oxide and / or ethylene oxide obtained polyether polyol having 2 to 8 terminal hydroxyl groups. 2) 20 to 100 parts by weight of an alkanolamine resin, ίο 3) 2 to 50 parts by weight of a diisocyanate or polyisocyanate and
4) contains 10 to 60 parts by weight of sucrose acetate isobutyrate,