JPH02242998A - Complex powder for papermaking imparting opacity - Google Patents

Abstract

PURPOSE:To obtain the subject powder having masking properties, high yield in producing process of paper, and imparting opacity causing excellent dispersibility and printability by fixing pigment on the surface of inorganic powder with fixing agent. CONSTITUTION:Pigment (preferably titanium oxide, zinc oxide or zirconium oxide having 0.1 to 1mu average granular diameter) is fixed on the surface of inorganic powder (preferably talc, calcium carbonate, clay, zeolite, sericite, kaolin or illite having 1 to 20mu average granular diameter) to afford the objective powder.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to a composite powder for paper making that imparts opacity by fixing a pigment to the surface of an inorganic powder, and more particularly relates to a light-shielding filler used in the paper manufacturing stage.

(Prior art) 1 Conventionally, paper fillers were mainly inorganic powders such as talc,
Mica, calcium carbonate, magnesium hydroxide, silica, alumina, etc. have been used.

However, since these materials are highly transparent, when used as fillers for paper, they have drawbacks such as prints showing through due to insufficient paper hiding power and ink bleed through. These drawbacks have hindered current efforts to reduce paper thickness.

In addition, pigments with hiding properties such as titanium oxide and zinc oxide are used.
It may be used as a filler alone or in combination with other extender pigments.

However, when using pigments alone, the yield rate on the paper surface is low and there are manufacturing problems, and even when mixed with extender pigments, the particle size
Due to differences in specific gravity, etc., they separated or became uneven, and a sufficient effect could not be obtained.

(Objective of the present invention) The object of the present invention is to provide concealment, high yield in the paper manufacturing process, and dispersibility. By doing so, it is possible to obtain a composite powder for paper making that has hiding properties, has a good yield in the paper manufacturing process, and provides opacity with excellent dispersibility and printability.

Of course, it is important that the pigment is linearly dispersed and fixed to a state close to that of primary particles.

Since the pigment is linearly dispersed and fixed, sufficient effects can be obtained without reagglomeration or separation.

The inorganic powder referred to in the present invention refers to inorganic extender pigments, which may be used alone or in combination.

The average particle diameter is preferably in the range of 1 micron to 20 microns; if the average particle diameter is less than 1 micron, the yield during paper making is poor (unpreferable).

The pigment referred to in the present invention includes at least one of titanium oxide, zinc oxide, and zirconium oxide with an average particle size of 0.1 to 1 micron, and is also mixed with colored pigments such as iron oxide and chromium oxide. It can also be used as

The ratio of the inorganic powder to the pigment of the present invention varies slightly depending on the required light-shielding performance and each particle size, but the pigment is preferably in the range of 2 to 30 parts by weight per 100 parts by weight of the inorganic powder.

The fixing agent used in the present invention includes methylhydrogen-resiloxane, silicone oil, paraffin, fatty acids having 12 or more carbon atoms and their esters, natural oils and fats such as wood wax, beeswax, palm oil, mink oil, and egg yolk oil. and their hydrogenated products, waxes such as castor wax, galvana wax, and microcrystalline wax, natural resins such as rosin and rubber, acrylic, styrene, vinyl chloride, vinyl acetate, nylon, and esters. Examples include synthetic resins such as urethane-based resins and olefin-based resins.

The above-mentioned fixing agents can be used alone or in combination.

The following two methods are preferable as a method for producing the composite powder for paper making which imparts opacity by fixing a pigment to the surface of the inorganic powder using a fixing agent according to the present invention.

1. Surface-treat the pigment or add a dispersant so that it is linearly dispersed in the oil layer, dissolve or disperse it in a solvent together with a fixing agent, mix with inorganic powder, and dry.

2. Disperse the pigment in the resin emulsion silane solution, mix with the inorganic powder, and dry.

The above methods can be used depending on the intended use.

Further, in order to prevent agglomeration during drying, it is more preferable to use a fluidized bed type, jet stream type, spray dryer, or the like.

The present invention will be explained in more detail with reference to Examples.

All formulations in the examples are expressed in weight proportions.

Example-1 Sodium hexametaphosphate 0. 300 parts of lχ aqueous solution 100 parts of zinc oxide 40 parts of acrylic emulsion solid content 150 parts of the above mixture was sufficiently fractionated using a homogenizer.

This was added to 1,000 parts of clay (average particle size: 4 microns), sufficiently kneaded with a Ni-Goo, and dried and pulverized with a Jet O Dryer manufactured by Seishin Enterprises.

The drying temperature is 80°C and the pressure of one nozzle is 4 kg/
It was a CD.

When this powder was observed using a transmission electron microscope, the zinc oxide was found to be almost uniformly attached to the clay.

Example 2 Sodium hexametaphosphate 0.1x aqueous solution 100 parts Titanium oxide 100 parts Acrylic Elsion solid content 50% 200 parts The above mixture was sufficiently dispersed using three rolls.

This was added to 1,000 parts of talc (average particle size: 8 microns), sufficiently kneaded with a Nigu, and dried and pulverized with a jet pulverizer 100AFG made by Albine.

The rotation speed of the classifier is 1200, and the pressure of the rotating nozzle is 5.
kg/cd.

The percentage of pancreatic rhinoceros was measured at 1 + 1.

→The light transmittance of the powder of Example 2, 42% talc alone, 65% talc, and a mixture of titanium oxide (titanium oxide lO%) was measured at the same time, but the titanium oxide tends to settle, making it difficult to measure accurately. could not.

Example-3 Paper was made using the powder of Example-2.

NoF Rudeslurry (solid content 50g), anionic sizing agent 1%, aluminum sulfate 1.5V Example-2 powder 20
% and stirred for IO minutes. This is made into paper using a square sheet machine and then pressurized using a press (3.5 kg/cd).
Dry. This paper was left in a constant temperature room at a room temperature of 20'C and a humidity of 12% for 24 hours to obtain paper with a basis weight of 35 g/nf. This paper was opaque, and when it was made, there was no pigment unevenness and the paper yield was good.

Comparative Example-1 1% anionic sizing agent and 1-5 μl of aluminum sulfate (average particle size 8
Micron) 20% was added and stirred for 10 minutes. This is made into paper using a square sheet machine and then pressurized using a press to produce 3.5 k paper.
g/cj) dried. This paper is heated at a room temperature of 20°C and a humidity of 12°C.
The paper was left in a constant temperature room of χ for 24 hours to obtain paper weighing 35 g/pot. Although this paper had poor opacity, when it was made, there was no unevenness of pigment and the paper yield was good.

Comparative Example-2 if) 1% anionic sizing agent and 1% aluminum sulfate were added to Repslurry (solid content 50g). Q/LUC (average particle size 8 microns) and 20% of a titanium oxide mixture (talc 91%, titanium oxide 9%) were added and stirred for 10 minutes. This is made into paper using a square sheet machine and then pressurized using a press machine.3.5
kg/d) dried. This paper is heated at a room temperature of 20°C and a humidity of 12°C.
% in a constant temperature room for 24 hours to obtain paper weighing 35 g/pot.

This paper had some opacity, but when it was made, pigment unevenness was observed and the paper yield was poor.

Example-4, Comparative Example-3 Using the papers obtained in Example-3, Comparative Example-2, and Comparative Example-3, a printing test was conducted using a letterpress printing machine, and the state of show-through was visually determined.

All inks and printing conditions were the same.

Table 1 Comparative Example 3 Paper Comparative Example 2 Gyen Comparative Example 3 No Paper Somewhat Yes As explained in the examples above, the composite powder for paper making that imparts opacity of the present invention has improved opacity. It has characteristics such as high yield rate in the paper manufacturing process, excellent dispersibility and printability, and the ability to reduce the thickness of paper.

Claims (1)

[Scope of Claims] 1. A composite powder for paper making in which a pigment is fixed to the surface of an inorganic powder using a fixing agent. 2. The composite powder for paper making according to claim 1, wherein the pigment contains at least one of titanium oxide, zinc oxide, and zirconium oxide with an average particle diameter of 0.1 micron to 1 micron. 3. The inorganic powder includes at least one of talc, calcium carbonate, clay, zeolite, sericite, kaolin, and illite with an average particle size of 1 to 20 microns. Composite powder for paper making.