DE2412516C2 - Coated pressure sensitive copier papers, coating slip and pigment material for use therein - Google Patents

Description

The invention relates to coated, pressure-sensitive copier papers, cladding-containing coating slips for Use in papler coatings and pigment materials for use in such Sirelch masses.

US Pat. No. 2,699,432 discloses a paper smear for use in pressure-sensitive papers which contains certain types of clay that are associated with certain organic compounds under Hcrvor-4 « Calling a discoloration can react when the clay and the organic compound in mechanical. Be brought into contact.

In GB-PS 11 47 480 it has already been proposed that micronized, i.e. finely ground, or precipitated Kleselerdegele To be entered in such paper stalk masses.

It has now been found that certain synthetic, kleselerdehaltlge Materlallen, welch-- Sllizlumdloxld Thus contain (SiOj) and alumina (AljOO, wherein the proportion of Al is ₂ Oj between 7.5% and 28% to Trockengewichtsbasls when their particle size reduced wlrC , are particularly effective in paper streaks.

The invention therefore provides a synthetic, silica-containing Plgmcüt-Materlal for use in paper

Coating slips containing a mixture of amorphous silicate oxide / aluminum oxide. In which the proportion of AljOi is between 7.5% and 28% on dry weight bsls, with the surface in the range from 300 to 800 ^mJ / g, the mean pore diameter (MPD) in the range from 4 to 10 nm. And the pore volume ( PV) are in the range from 0.5 to 1 ml / g and the particle size is in the range from 15 to 3 µm.

The synthetic, silica-containing pigment material of the present invention can be conveniently obtained. By subjecting certain silicon dioxide / aluminum oxide materials, which are useful as petroleum cracking analyzers, to a suitable grinding process in order to reduce their particle size to below about 15 .

Suitable milling works include milling in a ball mill, on a three-roll mill in one Colloid mill, etc. A water wet milling technique is preferably used as the milling technique, this being the case is used to bring the particles to 10 μm and particularly preferably to 5 μm to about 3 μm.

Excessive milling produces an inordinately high proportion of fine particles. which in the paper (■ ·> are absorbed and clog them. These fine particles support the color circulation less strongly and should therefore be avoided.

The preferred filler / aluminum oxide materials for use with pressure sensitive coatings are two materials commercially available as cracking catalysts, nilmlleh those with I.Ή n / w. 25 ",,

.Munilnliinioxldgchnll. These materials are an amorphous mixture of alumina and silica and they are known to have Lewls pew on their surfaces. These places are at the Color development of the copy materials valuable.

The synthetic silica-containing pigment material of the invention is advantageous in terms of color development considerably more reactive than the well-known Allapulglt and Silton-ion species which have hitherto been used in such paper layers have been used, and it is better than synthetic silica gels or phenolic resins which were also applied. As with the known clays, the material according to the invention can be attapulgite and Sillon can be mixed with kaolin coatings for use in the various applications.

In addition, the silica / alumina materials of the invention are cheaper to manufacture than silica gels and therefore they are more advantageous in terms of cost / performance.

Various paper coating latices are known from the aforementioned publications, which are used for binding The aluminum / aluminum oxide materials can be used with the paper including Slyrol / butadlene, acrylic ester or vinyl ester latices and various natural resins or gums In suitable solvents.

The invention also provides a coating slip for use in pressure sensitive copier papers, soft a synthetic, silicate-containing material as previously defined, together with a latex one synthetic resin or a solution of a natural resin or natural rubber as a binder. In the Table I below shows the physical parameters of the silica-containing materials according to the invention and the silica gels and clays used so far.

TabeUj I

ground, siliceous materials (according to the invention)

13% AI ₂ Oj 25% AI ₂ O ₃

Gels and clays
(previously known)

Silica gel attapulgite clay Siltonton

O (m - '/ g) 580 430 350 MPD (nm) 4.9 6.7 9.1 PV (mi / g) 0.7 0.7 0.8 TG (μΐϊΐ) 7th 7th 4th

O = surface PV = pore volume MPI) - miniser pore diameter ICi - particle size

25th
5.0

<0.05

30th
5.2

<0.05
7th

^l: .LNC method for studying this Materlallen in pressure-sensitive papers is because ^ in to determine the BLID-Intcnsliili which is in the course of the tent in relationship developed into a block of typed "X" on the pressure sensitive Paplersystem

The image line or reflectivity is measured using a standard 90 reflectometer (perpendicular to the paper) measured.

Examples 1 to 6

In the following examples, a commercially available, pressure-sensitive Ptpler was used as the standard, which was based on Sllton clay and kaolin. The materials according to the invention were on the front a suitable paper using a butylene / styrene latex as a binder and with the addition of varying amounts of water as a diluent. A standard one on the back Dye-coated paper was used to make the other component of the pressure sensitive System to deliver. The results are shown in Table II below. It should be noted that the dye intensity values (image intensities) provided by lower values of the reflectance can be specified.

Table II example

Time in the ball mill (hours) Particle size (μηι)

lc 2a 1 2 3

12 3 4 5

20 15 9 7 6

Reflectivity values
after 30 sec.

13% AI2O3 synthetic, containing gravel
material

20% kiesierhaltige material 80% kaolin

25% kiesie-containing material 75% kaolin

30% gossamer containing material 70% kaolin

50% siliceous material! 50% kaolin

Standard paper *)

Table II a

87.5 82.0 82.2 82.3 82.3

85.0 81.5 79.0 77.5 77.0

85.5 81.5 77.0 76.0 75.5

86.0 80.0 77.0 76.0 V 5.0

82.5 82.5 82.5 82.5 82.5

example

Time in the ball mill (hours) Particle size (μπι)

3a 4a 4 5 6

12 3 4 5

21 16 10 7 6

Reflectivity values
after 30 sec.

25% Al ₂ Oj synthetic, containing kieselei
material

20% kiesierhaltige material 80% kaolin

25% kieseliferous material 75% kaolin

30% gossamer containing material 70% kaolin

50% silica containing material 50% kaolin

Stand paper *)

87.5 84.5 82.0 82.5 82.0

87.5 84.5 82.0 81.5 82.0

87.0 82.1 79.0 81.5 79.0

87.0 81.0 78.0 77.5 76.5

82.5 82.5 82.5 82.5 82.5

"I The standard papers used in all experiments were IDF.M-I'apicrv. Manufactured by Wiggins (cane
Limileo. London. lingland.

The trial numbers with the suffix - a "are comparative examples. The particle size was millels
measured with a Coulier counter.

Examples 7 to 9

The color of the coated paper can advantageously be ^{improved with respect to its initial "whiteness 1} ". By adding shares of other, white ones to the silica-containing material according to the invention. In-house painters like zinc oxide and magnesium oxide can be entered. The addition of these materials excessively affects the color development of pressure-sensitive papers and improves the Welßgrid.

In the following, the influence of the addition of other metal oxides into the aluminum oxide will be discussed. materials shown on the starting bell switches.

A sample of aluminum silicon oxide with 13% aluminum oxide potassium was prepared by reacting an aluminum silicon oxide solution with aqueous sodium silicon oxide. Under the same conditions, similar batches were prepared which contained small amounts (approximately 2 %, on a dry-grown basis) of zinc oxide on the one hand and magnesium oxide on the other. This was carried out in such a way that the hydratable oxides were introduced from the sulfate salts by reaction with sodium silicate in the course of production

became. All materials were examined at a value of .10 ",. Klesolerdehaliigcni material / u kaolin and ground for ^{three hours in a ball mill to a particle size of elwa l} ) μm.

Example of response participants sysicm value of the image

reflection ·, erniö after .10 sec.

7 13% AhOi, synthetic 77

8 13% AIiOi ₁ synthetic, 78 '"which is nominal

Contains 2% zinc oxide

9 13% AI ₂ Oi, synthetic. 77

which nominal ¹ ^

Contains magnesium oxide

These results show that there is no noticeable effect on the intensity of the initial image produced by the addition of zinc oxide or magnesium oxide to the aluminum oxide: silicon dioxide structure. Magnesium oxide can also be added to the batch to improve other properties of the subsequent paper m coating, e.g. B. its "whiteness", whereby this can be carried out without subsequent influencing of the initial image intensity.

Example 10

The following shows the influence of aging on the image activity of papers which have been coated with synthetic, cleric-containing material containing 13% Al ₂ O ₁ .

A mixture of synthetic aluminum oxide: Slllzlumdloxld with 13% AljO> three hours with kaolin In an amount of 30% silica-containing material to 70% kaolin ground in the ball mill and then spread on a base paper as in the earlier examples. Schrelbmaschl- «o nenzclehen Shown in the catfish described above and the measurements of the reflexion capacity 30 Performed seconds after formation. The paper was stored at 20 "C and 70% relative humidity, and image activity was assessed over an eight week period. The results are Below along with those obtained with a commercially available pressure-sensitive paper were listed as a comparison. From this it can be seen that the activity of the with the mixture of synthetlschcm Aluminum oxide: Slllumdloxld coated paper against atmospheric deactivation Is less unfair than be! commercial paper.

Reflectivity values *

initially 2 weeks 8 weeks

System synthetic 77 77 81

Aluminum oxide: silicon dioxide

commercially available, pressure-sensitive 82.5 86 88

Copy paper

The following investigations still show the importance of the selection of the silicon oxide / aluminum oxide ratio in relation to the initial flower development. The materials were all reduced to about 9 (im ground.

example Respondent system Worth of the picture
reflective ability
after 30 sec. 5 a 100% SiO ₂ 87.8 11 ' 7.5% Al ₂ O ₃ 81.0 12th 13.0% Al ₂ O ₃ 77.0 13th 20.0% AI ₂ O ₃ 79.0 14th 25% Al ₂ O ₃ 79.0 6a 30% AI ₂ O ₃ 89.0 7a 100% Al ₂ O ₃ 90.0

The synthetic, silica-containing pigment material according to the invention can be used to replace the entire Sllton clays or phenolic resin In normal, known coating systems or to replace part of them be used. The synthetic, high-calorie material is preferably used to protect his / ur To replace half of the normally used Sllton clay, which has better flow properties Coating results because the coating is less thixotropic.

In addition, the pH of the coating, which is normally raised to 11, can be reduced to one pH value can be reduced in the range from 6 to 8, which prevents the paper from being stored before it is used / u seems to improve. The synthetic, silica-containing material according to the invention can also be used in so-called "Closed" pressure-sensitive copier papers are used, which are with neighboring Coatings are produced, each containing the usual dyes and those which are reactive towards the dye Painting lalls included.

Claims (4)

Patent claims: 1. Coated, pressure-sensitive copier paper for use in connection with a paper carrying a dye, characterized in that the pressure-sensitive copier paper carries at least one surface of a conventionally dried coating slip, which together with a latex of a synthetic resin or a solution of a natural resin or Natural rubber as a binder contains a synthetic, silica-containing material and the latter is a mixture of amorphous silica / aluminum oxide, in which the proportion of Al ₂ O _{3 is} between 7.5% and 28% on a dry weight basis, with the surface area in the range from 300 to 800 m ^J / g, the mean pore diameter (MDP) Im ίο range from 4 to 10 nm, the pore volume (PV) in the range from 0.5 to 1 ml / g and the particle size Im Range from 15 to 3 μm, preferably between 10 and 3 μm. 2. Coated, pressure-sensitive, closed copier paper which carries a coating of a layer containing a dye and an adjacent layer which is reactive towards the dye, characterized in that the layer which is reactive towards the dye was formed from a coating slip which, together with a latex of a synthetic Resin or a solution of a natural resin or natural rubber as a binder contains a synthetic silica-containing material and the latter is a mixture of amorphous silicon dioxide / aluminum oxide, in which the proportion of Al ₂ O _{1 is} between 7.5 hours and 28% on a dry weight basis, with the surface in the range from 300 to 800 mVg, the mean pore diameter (MDP) in the range from 4 to 10 nm, the pore volume (PV) in the range from 0.5 to 1 ml / g and the particle size in the range from 15 to 3 μm , preferably between 10 and 3 μm. 3. Paper coating slip suitable for use in pressure-sensitive copier papers according to claim 1 or 2, which contains a synthetic resin containing a latex of a synthetic resin or a solution of a natural resin or natural rubber as a binding agent, characterized in that the earth containing material is a synthetic, synthetic material which contains a mixture of amorphous silica / alumina. In which the proportion of Al ₂ O _{3 is} between 7.5% and 28% on a dry weight basis, with the surface area in the range from 300 to 800 mVg, the mean pore diameter (MDP) in the range from 4 to 10 nm, the pore volume (PV ) in the range from 0.5 to 1 ml / g and the particle size in the range from 15 to 3 μm. 4. Synthetic, silica-containing pigment material suitable for use in a paper coating slip 3n according to claim 3 for pressure-sensitive papers, which contains a mixture of amorphous silicate oxide / aluminum oxide. In which the proportion of Al ₂ O _{5 is} between 7.5% and 28% on a dry weight basis, with the surface area in the range from 300 to 800 m '/ g, the mean pore diameter (MDP) in the range from 4 to 10 nm and the The pore volume (PV) is in the range from 0.5 to 1 ml / g, characterized in that its particle size is in the range from 15 to 3 μm and it is preferably produced by water grinding.