DE3837746C1 - - Google Patents

Abstract

A paper-like or cardboard-like raw material containing inorganic fibres, particulate inorganic additives and organic binders or flocculents is characterized in that (1) the particulate inorganic additives comprise 40-80 wt. % of the dry mass of the raw material; (2) the particulate inorganic additives contain (2.1) a basic filler of which at least 20 wt. % has a particle size < 2 mu m and not more than 20 wt. % has a particle size > 20 mu m and < 0.5 mu m, and (2.2) an anionic flocculating active pigment of which at least 50 wt. % has a primary particle size < 2 mu m; (3.1) the organic flocculant is a cationic polymeric carbohydrate with a mean molecular weight between 100 000 and 2 000 000 and a degree of substitution between 0.01 and 0.3 and amounts to 0.5 to 6 wt. % of the dry mass of the raw material; (3.2) 1000 g of basic filler may bind, with floc formation, not more than 0.1 mmol of cationic carbohydrate and 1000 g of anionic flocculating active pigment binds, with floc formation, at least 0.1 mmol of cationic carbohydrate.

Description

The invention relates to a paper, cardboard or cardboard-like Material with a very high proportion of inorganic Ingredients, namely inorganic fibers and inorganic particulate additives, d. H. of fillers and pigments.

It is well known that the strength of paper on the Base of organic fibers through the formation of hydrogen bonds between the organic fibers. Continue it is known that inorganic fillers by mechanical separation the fibers from each other are used for the hydrogen bonds reduce available fiber areas or bindable Block spots on the fiber and through weaker fiber-filler-fiber bonds replace, using finely divided fillers reduce the strength particularly strongly.

So are in the manufacture of paper or cardboard-like Materials only inorganic fibers and fillers, i.e. substances, that have no hydrogen bonding ability, the materials obtained have only low strengths.

EP-A 1 09 782 and EP-A 00 27 705 are paper-like Materials known to be inorganic fibers, such as glass fibers or mineral wool fibers, inorganic particulate fillers, like clay and bentonite, as well as hydrolyzed starch contain organic binder. However, it becomes Improve strength and reduce brittleness organic phases are also used.  

DE-A 26 06 487 describes a process for continuous Manufacture of molded parts known, the inorganic fibers, a Contain silica sol and anionic starch. These molded parts however, do not contain inorganic particulate Fillers.

EP-B 00 80 986 (AT-E 13 777) is a paper manufacturing process known, after which a product is obtained that organic fibers, d. H. Pulp fibers, mineral Fillers, anionic colloidal silica and cationic Contains guar. Such a product is because of its high Share of organic fibers combustible and therefore for many High temperature applications not suitable.

From US-A 32 53 978 a method for producing a porous inorganic sheet known to be the inorganic fiber and / or larger flakes, an anionic silica sol and contains cationic starch, the inorganic fibers first mixed with the silica sol and this mixture then the cationic starch is added. Such a thing However, leaf does not contain any finely divided inorganic Fillers and has insufficient strength.

GB-A 21 27 867 is a low-density fiber material known, the inorganic fibers, inorganic fillers and contains a high proportion of cationic guar. Both inorganic fillers are standard fillers, which are used in relatively small quantities. Further is used to deposit the guar on the inorganic fibers borax added.

A fibrous sheet material is known from GB-A 20 31 043, the inorganic fibers in a matrix of plastic clay contains. The material can also be bentonite Regulation of drainage speed included. As  The binder used is hydrolyzable starch. The material also contains a relatively high proportion of cellulose fibers.

From US-A 37 02 279 is the production of a thermal Insulating material known, wherein inorganic fibers with a Binding agents are mixed from an inorganic sol, whereupon the sol is gelled. This material does not contain any particulate inorganic additives. It won't be organic Binder used. The material is after drying sintered.

Finally, EP-B 00 41 056 describes a method for Manufacture of paper known in which a fiber and aqueous paper stock containing cationic starch and is dried. The fibrous material contains at least 50% by weight Pulp fibers. The paper stock is pre-formed Binder mixed, which colloidal silica and contains cationic starch. Because of the high proportion of The paper obtained is flammable to pulp fibers.

The invention has for its object to provide a paper, cardboard or to create cardboard-like material, on the one hand is non-flammable and on the other hand high strength and Has flexibility and is easy to process. These properties were previously incompatible, i. H. for the production of fiber materials with high strength and flexibility as well as with good Processability has so far been a relatively high proportion considered necessary on organic fibers, thereby the Flammability naturally increased.

To achieve this object, the invention proposes paper, cardboard or cardboard-like materials containing inorganic fibers, inorganic particulate additives and organic binders or Flocculants, which are characterized by

• (1) that the particulate inorganic additives up to 40 to Make up 80% by weight of the material,
• (2) that the inorganic particulate additives from
  • (2.1) a base filler, of which at least 20% by weight has a particle size of <2 µm and not more than 20% by weight has a particle size of <20 µm on the one hand and <0.5 µm on the other, and
  • (2.2) an anionic flake-forming active pigment, of which at least 50% by weight has a primary particle size of <2 μm, is composed,
• (3.1) that the organic flocculant is a cationic polymer Medium molecular weight carbohydrate from 100,000 to 2,000,000 and a degree of substitution of Represents 0.01 to 0.3 and in an amount of 0.5 to 6 % By weight, based on the dry matter of the material, is present and that
• (3.2) 1000 g base filler not more than 0.1 mmol and 1000 g anionic flake-forming active pigment at least 0.1 mmol of cationic carbohydrate with formation of flakes bind assets.

The materials according to the invention are not flammable. they meet the requirements of DIN 4102 class A. Due to The good strength properties of the invention Materials similar to paper, cardboard and cardboard on the Easily process the base of cellulose fibers. The Production of the materials can be done on the usual paper, Cardboard or cardboard machines take place.

The good strength properties are therefore surprising because it was previously believed that at high filler levels and with increasing particle fineness the strength values decrease dramatically. The strength values of the invention In contrast, materials increase within wide limits with increasing Amounts and increasing particle fineness of the particulate inorganic additives.

"Particulate inorganic additives" means no fibrous additives according to the invention, since the length of the Fibers generally on the order of millimeters  lies. "Particle size" means the largest dimension of a particle, e.g. B. important with flattened particles is. The particles of the anionic flake-forming active pigment sometimes show a tendency to form larger agglomerates. According to the invention, the particle size is therefore understood to mean the Primary particle size.

The improvement in strength properties is likely due to the fact that the anionic flocculating Active pigment and the cationic polymeric carbohydrate on the one hand to the inorganic fibers and on the other hand to the add inorganic particulate base fillers. The Base filler particles settle on the fiber surfaces and in this way prevent them from sliding together smooth inorganic fibers, creating a non-slip fiber fleece is obtained. Inorganic fibers are unable to neither by hydrogen bonding, nor by crosslinking in Combine with shrinkage to train strengths like it is the case with vegetable fibers. The strength of a leaf made of purely inorganic fibers is based on "bonding" of the individual fibers with each other at the fiber contact points with the help of organic binders. Because of the low Such a non-woven fabric has flexibility of inorganic fibers relatively few fiber-to-fiber touch points, moreover is the retention of organic binders during drainage in the conventional paper making process extremely low. The finished The product is therefore of low strength.

The basic fillers used according to the invention can be based on their surface size and structure as well as their Charge properties together with a suitable cationic Carbohydrate form a flake. When flocculated in water System, the inorganic fibers are embedded by the filler. The addition of the filler accordingly leads to the invention both the number of points of contact (fiber-fiber;  Filler fiber; Filler-filler) as well as the retention of the Carbohydrate increased. Good structural strength is only achieved if possible all fiber-fiber crossing points completely and are embedded without defects in filler and that Flocculant is evenly distributed. This is only possible with a suitably trained flake. Control of flocculation takes place according to the invention with the help of the flake-forming active pigments. These can be due to their anionic charge potential move the flocculation point and carry over it through the formation of a micro flake together with the cationic carbohydrate for a good distribution of the same at. The anionic flake-forming active pigments can also defects in the filler-filler and fiber-filler composite shut down.

The reaction mechanism described clarifies that it is This is a very complex system, which is also synergistic Effects can occur. The individual components of the materials according to the invention - i.e. fibers, basic filler, anionic flake active pigment and cationic Carbohydrate - must therefore in terms of type and amount added be precisely coordinated.

There are no restrictions on the inorganic fibers. An object of the invention, however, is to contain fiber Provide materials in which the potentially carcinogenic Asbestos fibers thanks to fibers that are harmless to health are replaced. These include u. a. Glass fibers, mineral fibers, Silicic acid fibers, basalt fibers and / or aluminum oxide fibers. The thickness and length of the inorganic fibers can be within further areas fluctuate. Preferably have at least 80% of the inorganic fibers have a length in the range of 1 to 6 mm. There can also be mixtures of inorganic fibers that are differ in composition, length and thickness, be used.  

Also with regard to the particulate inorganic base fillers there are no restrictions. For example, are suitable SiO₂, kaolin, aluminum oxide, bleaching earth, gypsum, calcium carbonate, Titanium dioxide, zinc oxide, perlite, vermiculite and / or other known paper fillers or fillers for Plastic masses and colors.

Give some of these basic fillers, like gypsum and bleaching earth when heating water of crystallization or water of adsorption from time to time act fire retardant in this way. A comparable effect has calcium carbonate, which is carbon dioxide at higher temperatures delivers.

The content of basic inorganic fillers is generally 35 to 75% by weight, preferably 55 to 70% by weight on the dry mass of the material.

The inorganic base filler preferably has 35 to 99 wt .-% a particle size of <2 microns and not more than 10 wt .-% a particle size of <20 microns.

The anionic flake active pigment is preferred Aluminum hydroxide, bentonite or colloidal amorphous SiO₂. The content of active pigments is generally 1 to 15, preferably 2 to 10 wt .-%, based on the dry matter of the material.

If an anionic colloidal amorphous SiO₂ is used, then this is preferably in the form of a 30-40% aqueous dispersion used. Anionic silica sols which by contacting a dilute water glass solution with a acidic cation exchanger and aging of the sol obtained have been. They are dispersed in an alkaline medium, that reacts with the silicon dioxide surface and there one generated negative charge. Bump because of the negative charge  the particles mutually off and thus cause stabilization of the product. Suitable commercial products are e.g. More colorful the name Ludox (trademark of the Du Pont company), although other products can be used.

If aluminum hydroxide is used as the active pigment, this can in statu nascendi from an alkali aluminate and an acid, preferably from sodium aluminate and sulfuric acid, or from an aluminum salt and alkali, preferably aluminum sulfate and caustic soda.

If bentonite is used as the active pigment, it becomes more swellable Alkali bentonite preferred.

The ratio between the inorganic particulate Additions and the cationic polymeric carbohydrate preferably chosen so that there is no excess charge is so that an optimal flake forms.

Preferred polymeric carbohydrates are cationic starch, cationic amylopectin, cationic galactomannans (e.g. guar or Cassia) and / or cationic carboxymethyl cellulose. The Carbohydrates can thereby be cationized in a manner known per se that the optionally hydrolyzed starting carbohydrates quaternized with quaternary ammonium compounds will. However, the carbohydrates can also be dry-cationized be cationized. The cationic carbohydrates cationic polyvinyl alcohols can also be added will.

The polymeric cationic carbohydrate content is in generally 1 to 5, preferably 1 to 3 wt .-%, based on the Dry mass of the material. It essentially depends on that desired application area. If you want high-quality materials Produce temperature resistance, that's what polymer  cationic carbohydrate used in smaller amounts. Materials for use at high temperatures are for example sealing materials in chemical and engine construction as well as temperature resistant filter materials for hot gases and Liquids. Furthermore, the materials according to the invention even at higher carbohydrate concentrations than insulating materials in construction, especially in drywall, e.g. B. as cable routes and fire insulation, for fire doors, wall and ceiling panels, backing layers for heat-insulating materials as well as fireproof displays for advertising purposes (in department stores) be used. Another important area of application is in vehicle construction, since the materials according to the invention in addition to their Temperature resistance a low specific weight to have. Even with a higher content of cationic carbohydrate there is no ignition of the material, since that cationic carbohydrate just charred.

The cationic polymeric carbohydrate generally has one average molecular weight from 200,000 to 1,000,000, preferably from 300,000 to 800,000, and a degree of substitution from 0.02 to 0.15.

The materials according to the invention can also be cationic, contain anionic or non-ionic retention aids. These are usually those in the paper industry usual retention aids, which are preferably in Quantities of 0.02 to 0.2 wt .-%, based on the dry weight of the Material to be added.

As a retention aid, for example, a cationic Polyacrylamide with a molecular weight of 1 to 10 million or a polyethyleneimine with a molecular weight of 80,000 up to 300,000 can be used.  

The materials of the invention can also wet strength agents included, preferably in an amount of 0.2 to 5% by weight, based on the dry matter of the material. Suitable Wet strength agents are, for example, urea or melamine-formaldehyde resins and polyamide amine epichlorohydrin resins.

The materials according to the invention also include three-dimensional ones Molded body. These include a. Pipes, shells, filter bodies, Insulating walls or sealing elements.

The materials according to the invention are preferably thereby prepared that an aqueous dispersion of the inorganic Fibers and the particulate inorganic base fillers mixed with an aqueous suspension of the active pigment and this mixture shortly before shaping the cationic polymer Carbohydrate adds. The shape can e.g. B. on a paper cardboard machine. In this case it speaks one of a leaf formation. The production of the three-dimensional Shaped bodies are preferably made by the fiber casting process. But it is also possible to make the still wet sheet in a three-dimensional Put the mold down and dry.

Preferably, the shaping is carried out after Add the cationic polymeric carbohydrate in aqueous Mixture have formed flakes.

The shaping is preferably carried out after at least 10 seconds after the addition of the cationic polymer Carbohydrate through. The retention aid is preferred after the addition of the cationic polymeric carbohydrate added.

In order to obtain homogeneous products, the inorganic Fibers and the basic inorganic fillers before production  the dispersion is preferably separated from a wet dispersion subjected, whereupon the separate dispersions together mixed. This ensures that everyone Part by selecting a suitable stirring speed and Stirring time is optimally dispersed. For example, hang the dispersion parameters on the nature, length and thickness of the inorganic fibers or of the nature, the particle size and the specific weight of the base filler particles from.

The mixed dispersion of inorganic fibers and inorganic The basic filler particles then become the aqueous dispersion of the active pigments, whereupon briefly (about 10 to 30 seconds) added the cationic carbohydrate before leaf formation becomes. The retention aid is then added.

The invention is illustrated by the examples below.

Examples 1 to 6

Long-fiber glass fiber (2-6 mm) is predispersed in water. Then a separate predispersion of mineral fibers is used a fiber length of up to about 3 mm. As a mineral fiber z. B. the commercial product "Inorphil" (trademark of the company Laxå, Sweden, used). The proportions by weight between glass fibers and mineral fibers are given in Table I. Subsequently a dispersion of kaolin (basic filler) is produced. The particle sizes and the proportions by weight of those used Varieties of kaolin are also shown in Table I.

The three predispersions are made with a dispersion of colloidal, amorphous SiO₂ mixed thoroughly. The water content the dispersion is 60-70% by weight.  

Then a solution of cationic starch (e.g. commercial product Amÿel, Q-Tak 210 from Cerestar) added (solids content the solution = 1% by weight). The weight percentages of colloidal SiO₂ and cationic starch are also shown in Table I.

After the cationic starch has been added, flakes form. To Example 6 becomes a cationic polyacrylamide as a retention agent (e.g. Nalco 47-32; trademark of Nalco Chemical Co.) added in the amount specified in Table I.

About 20 seconds after the cationic starch is added, the aqueous mass on a laboratory sheet formation system according to Rapid-Koethen brought, whereupon the aqueous phase is suctioned off. You get a sheet that has a density of about 0.3 mm after drying. The tensile strengths of the test sheets are given in Table I.

As can be seen from Examples 1 to 6, the strength decreases surprisingly and contrary to the current state of knowledge of Paper industry with increasing basic filler content and larger Particle fineness with very good retention values to a great extent.

Comparative Examples 1 and 3 already show the influence of Particle fineness, while Comparative Examples 3 and 4 den Influence of the filler content on the mechanical strength demonstrate.

Examples 2, 5 and 6 according to the invention show the through the Addition of the anionic flake-forming active pigment conditional Strength increases, the according to Example 5 compared to the Example 2 increased strength due to the higher proportion and the higher particle fineness of the base filler is due.  

Example 6 shows that by using a retention aid the strength against the material of the next comparable example 5 can be further increased can.

Examples 7-10

The fiber and filler predispersions are produced as in Examples 1 to 6, with those given in Table II Substances and weight ratios are used. The Mixing the predispersions with the other ingredients as well as the leaf formation are also as in the examples 1 to 6 performed.

In Example 7, the active pigment instead of the colloidal, amorphous silica an aluminum hydroxide dispersion used in situ from aluminum sulfate and sodium hydroxide was produced.

In example 8, bentonite is used as the active pigment. The Example 9 was used as a comparative example (without active pigment) added.

Examples 7 to 10 are intended to influence the various flake-forming active pigments on the strength properties the non-combustible inorganic materials according to the invention to be shown. The selection and amount of flake forming Active pigment is largely dependent on the properties of the base filler dependent. The amount of organic aids used, like carbohydrates, is due to the demands on the Non-flammability limited to a great extent. By adding Active pigments for the basic filler are used in the suspension "shifted" the most favorable flocculation area, and only this provides acceptable mechanical strength.  This is documented by comparing the strengths of the materials according to Examples 1, 3 (Table I) and 9, where no active pigment was used, with each associated values of the other examples.

Examples 11-15

The preparation of the predispersions, the mixing of the dispersions and the sheet formation are as in Examples 1 carried out to 6. The individual substances and theirs Parts by weight are given in Table III. The one in this Examples given in the table show that various Cationic carbohydrates can be used if they are an appropriate degree of substitution (DS) and an appropriate one Have molecular weight.

In Example 15 a combination of two different ones was used Carbohydrates used, which are also useful strength values results.

Corresponding sheets can also be on suitable paper or Cardboard machines (wire or wire) in any thickness getting produced. The total retention depends on the recipe and machine type between 85 and 95%. Depending on the type and The amount of fiber materials and fillers used can do that specific weight varies in ranges from 500 and 1000 kg / m³ will. The insulation ability and thus the possible application depends mainly on the specific weight of the material produced decrease while the temperature resistance in the first Line is directed to the melting point of the fibers. In the specified Examples of recipes would be to replace the glass fiber with other fibers with a higher temperature resistance without problems and without adversely affecting the mechanical property.  

Table I

Table II

Table III

Claims (24)

1. Paper, cardboard or cardboard-like material containing inorganic fibers, inorganic particulate additives and organic binders or flocculants, characterized in that

• (1) that the particulate inorganic additives make up up to 40 to 80% by weight of the dry mass of the material,
• (2) that the inorganic particulate additives from
  • (2.1) a base filler, of which at least 20% by weight has a particle size of <2 µm and not more than 20% by weight has a particle size of <20 µm on the one hand and <0.5 µm on the other, and
  • (2.2) an anionic flake-forming active pigment, of which at least 50% by weight has a primary particle size of <2 μm, is composed,
• (3.1) that the organic flocculant is a cationic polymeric carbohydrate with an average molecular weight of 100,000 to 2,000,000 and a degree of substitution of 0.01 to 0.3 and in an amount of 0.5 to 6% by weight on the dry matter of the material, and that
• (3.2) 1000 g base filler not more than 0.1 mmol and 1000 g anionic flake-forming active pigment are able to bind at least 0.1 mmol cationic carbohydrate with flake formation.

2. Material according to claim 1, characterized in that the Amount of particulate inorganic additives (1) 50 to 75 wt .-%, preferably 60 to 75 wt .-%, based on the Dry mass of the material. 3. Material according to claim 1 or 2, characterized in that the inorganic fibers glass fibers, mineral fibers, Silicic acid fibers, basalt fibers and / or aluminum oxide fibers represent. 4. Material according to one of claims 1 to 3, characterized characterized in that at least 80% of the inorganic fibers Have a length in the range of 1 to 6 mm. 5. Material according to one of claims 1 to 4, characterized characterized in that the particulate inorganic base fillers (2.1) SiO₂, kaolin, aluminum oxide, bleaching earth, gypsum, calcium carbonate Titanium dioxide, zinc oxide, perlite and / or vermiculite  represent. 6. Material according to one of claims 1 to 5, characterized characterized in that the content of inorganic base fillers (2.1) 35 to 75, preferably 55 to 70 wt .-%, based on the Dry mass of the material. 7. Material according to one of claims 1 to 6, characterized characterized in that the inorganic base filler (2.1) to 35 up to 99% by weight a particle size of <2 µm and no more than 10% by weight has a particle size of <20 µm. 8. Material according to one of claims 1 to 7, characterized characterized in that the anionic flake-forming active pigment (2.2) Aluminum hydroxide, bentonite or colloidal amorphous SiO₂ represents. 9. Material according to claim 8, characterized in that the Aluminum hydroxide in statu nascendi from an alkali aluminate and an acid, preferably from sodium aluminate and sulfuric acid, or from an aluminum salt and alkali, preferably from aluminum sulfate and caustic soda. 10. Material according to one of claims 1 to 9, characterized characterized in that the ratio between the inorganic particulate additives (2) and the cationic polymer Carbohydrate (3) is chosen so that no excess charge is available. 11. Material according to one of claims 1 to 10, characterized characterized in that the cationic polymeric carbohydrate (3) cationic starch, cationic amylopectin, a cationic Galactomannan and / or cationic carboxymethyl cellulose represents.   12. Material according to one of claims 1 to 11, characterized characterized in that the content of cationic polymer Carbohydrate (3) 1 to 5, preferably 1 to 3 wt .-%, based on the dry mass of the material. 13. Material according to one of claims 1 to 12, characterized characterized in that the cationic polymeric carbohydrate (3) by reacting the starting carbohydrate with a quaternary Ammonium compound has been obtained. 14. Material according to one of claims 1 to 13, characterized characterized in that the cationic polymeric carbohydrate (3) an average molecular weight of 200,000 to 1,000,000, preferably from 300,000 to 800,000 and one Degree of substitution from 0.02 to 0.15. 15. Material according to one of claims 1 to 14, characterized characterized in that it is additionally cationic, anionic or contains non-ionic retention aids. 16. Material according to any one of claims 1 to 15, characterized characterized in that the retention aid in an amount of 0.02 to 0.2 wt .-%, based on the dry weight of the Material, is present. 17. Material according to claim 15 or 16, characterized in that the retention aid is a cationic polyacrylamide with a molecular weight of 1 to 10 million or a cationic polyethyleneimine with a molecular weight of Represents 80,000 to 300,000. 18. Material according to one of claims 1 to 17, characterized characterized in that it contains additional wet strength agents.   19. Process for producing a material according to a of claims 1 to 18, characterized in that a aqueous dispersion of inorganic fibers and particulate inorganic base fillers (2.1) with an aqueous Suspension of the active pigment (2.2) mixed and this mixture shortly before shaping the cationic polymeric carbohydrate (3) is added. 20. The method according to claim 19, characterized in that The shaping is carried out after adding the cationic polymeric carbohydrate (3) in the aqueous mixture flakes have formed. 21. The method according to claim 19 or 20, characterized in that the shape after at least 10 seconds after the addition of the cationic polymeric carbohydrate (3) is carried out. 22. The method according to any one of claims 19 to 21, characterized characterized in that after the addition of the cationic polymeric carbohydrate (3) the retention aid is added. 23. The method according to any one of claims 19 to 22, characterized characterized in that the inorganic fibers and the inorganic basic fillers (2.1) and active pigments (2.2) the generation of the dispersion separately from a wet dispersion be subjected. 24. The method according to any one of claims 19 to 23, characterized characterized in that the material per se known paper, cardboard or cardboard machine, or if there is it is three-dimensional shaped bodies, according to the fiber casting process  or by deforming a still wet fibrous web will be produced.