FI95401C - A method for producing at least a substantially non-combustible product from a fibrous raw material and a thermal insulation material and an asphalt additive prepared by the method - Google Patents

Abstract

The invention relates to organic fiber-based products and a method of manufacturing such products. According to the method, the fibrous raw material is milled together with a fire-retardant agent to a desired degree of defibering to the end of producing an at least essentially fire-retardant product. According to the invention, the fibrous raw material is admixed with at least a portion of the amount of the fire-retardant agent to be used, after which the material is milled to a desired degree of defibering using a refiner capable of exerting a milling action. Accordingly, when making a product suited for use as thermal insulation, 1/4 - 1/2 of the fire-retardant material is introduced to the fibrous base material prior to defibering in anhydrous form and 1/2 - 3/4 of the fire-retardant material is introduced to the fibrous base material after defibering in hydrous form. According to the invention, recycled paper can be used in the production of an at least essentially fire-retardant organic fiber-based material in which the anhydrous component incorporated therein swells during moisturizing, binds the fibers to each other and thus achieves a structure free from self-compressive settling.

Description

95401

A method for producing at least a substantially non-combustible product from a fibrous raw material and the thermal insulation material and asphalt additive produced by the method 5

The present invention relates to a method for producing vegetable fiber products according to the preamble of claim 1.

According to such a method, the fibrous raw material is ground together with 10 flame retardants to the desired fineness to produce at least a substantially non-combustible product.

The invention also relates to a thermal insulation material according to claim 9 and an additive according to claim 16.

Such a material consists of vegetable fibers ground to the desired fineness and a flame retardant mixed with them.

The material according to the invention is particularly suitable for use as a thermal insulator and also as an additive for, for example, road surfacing agents and the like.

The recycling and reuse of waste materials has gained a major 25 foothold in today’s industrialized world.

In order to utilize waste paper, methods have been developed that can be used to make thermal insulation, for example. Such e.g. There are many insulation materials on the market called pulp wool or eco-wool, and there are a large number of patents for them. Thus, since -77 alone, 50 pieces of wood fiber thermal insulation, their flame retardant composition and methods for making them, and binder compositions for bonding these fibers together have been patented in the United States alone. A few patents also deal with the sterilization of said cellulose wool insulation to improve its shelf life in the insulation space.

The thermal insulation capacity of materials suitable for the thermal insulation of a building is based on the fact that the insulation prevents the movement of air in the space to be insulated. The ideal insulator would be such that it would, to a certain extent, also prevent the thermal movement of the molecules. Insulation materials in the latter category include e.g. so-called aerogels with a pore size of the order of nanometers. Insulation can also be improved by using gases inside the insulator that have poor thermal conductivity and solid materials that effectively reflect thermal radiation and poorly conduct heat. The most effective insulation is, of course, a vacuum combined with many reflective surfaces placed in layers. However, it is not yet economical to use such exotic insulation materials to insulate a normal building and the like.

15

The thermal conductivity of air is 0.0253 W / m ° C, which is reached or very close to it with polystyrene foam with many reflective surfaces and small pore size. With the best natural material, the 1st cap has a thermal conductivity of the order of 0.045 20 W / m ° C, with a density of 140 kg / m3.

• ·

The typical so-called the thermal conductivity values of the cellulose or Eco-wool insulation are at best about 0.034 to 0.036 W / m ° C. The corresponding thermal conductivity of e.g. mineral wool is of the order of 0.040 W / m ° C and sometimes 0.038 W / m ° C. In this case, pulp-. , the density of the insulation is preferably 30 to 36 kg / m 3 and the density of the mineral wool is 30 to 80 kg / m 3, respectively. The difference is due to the difference in thermal conductivity of the fibrous materials. With mineral wool, the best insulation values are achieved, as with many other materials, at a density of about 40 to 60 kg / m3.

The advantages of thermal insulation made of vegetable fibers are e.g.

• · 1 compared to mineral wool insulation, they have good thermal insulation and low production costs. Since waste paper can be used as a starting material 35, the competitiveness of these products will be further improved in the future.

3,95401

Typically, pulp is made by tearing the paper and grinding it with a hammer mill, for example, and mixing a flame retardant with the fibers to make the insulation non-combustible and uncooked. At the same time, many flame retardants act as incinerators for the growth of fungi and other micro-crops. The most typical such substances are boron compounds, salts of phosphoric acid, antimony compounds, urea, etc., i.e. typically the same substances already used for all other flame retardant purposes.

10

As an example of the prior art, U.S. Patent No. 4,804,695 discloses grinding a fibrous material - either wood or (waste) paper - together with boric acid powder (14% boric acid by weight of the fibers) using a hammer mill for grinding.

There are some drawbacks to the current pulp wool manufacturing technology. Thus, a hammer mill flattens the fiber but does not fibrillate it like actual grinders. When flattened, the fiber 20 becomes a shape that is unfavorable for the thermal insulation function.

Furthermore, it would be advantageous from a manufacturing point of view to mix all the necessary chemicals, such as flame retardants and preservatives, even before grinding, in order to make them evenly distributed. This, in turn, is not possible with fibrillating refiners. The reason for this is as follows:

Typical flame retardants, such as borax or boric acid or soda or mixtures thereof, are used in crystalline form to enhance flame retardancy. It is therefore desired to use borax and the like as flame retardants, in particular in crystalline liquid form, so that the crystalline water released at the lowest possible temperature binds heat and reduces the hap-35 pea around the fiber. Correspondingly, anhydrous borax or any other similar crystalline water-binding material subsequently binds crystal-water if it is introduced into the material as a crystalline anhydrous, assuming that crystalline water is available in the environment, e.g.

The ten crystal water molecules of borax are released at a temperature of 5 ° C at 60.8 ° C, whereby borax is converted to the pentahydrate and / or tetrahydrate and later to the dihydrate at 95 ° C. When grinding waste paper, for example, a power of about 100 kWh / ton of material is typically used in dry grinding. This slightest use of power raises the temperature of the fibrous material and the ensuing air and additives so that the crystalline materials "melt" into their own crystal water and clog all the cracks in the grinder blade.

In addition to the actual cost of the insulation material, the installation of the insulation 15 in place is a significant cost factor in the thermal insulation of buildings.

The cheapest way to install the insulation is to blow it into place with airflow. Pulp and other inflatable insulators 20 have traditionally been best suited for applications that are insulators on horizontal surfaces where it is not essential even if the insulation accumulates to some extent with age. For this reason, their market has been mainly in the insulation of the upper floors of buildings and to some extent the lower floors. There are hardly any of these depressing insulators installed on the wall insulation as such.

When blowing e.g. cellulose wool or mineral wool into an insulated gap in the wall of a building, for the reason described above, it has always been necessary to blow a binder which binds the fibers together, preventing the insulation from settling.

However, the addition of binders has many disadvantages: - they always bring moisture to the insulated space 35 - binders require more flame retardant - most binders either contain volatile chemicals or are a desirable nutrient for microbes and mycelium.

5,95401

The object of the present invention is to obviate the drawbacks associated with the prior art and to provide a completely new method for producing vegetable fiber-based products which are suitable for use, for example, as inflatable thermal insulators and as additives for various hot-applied masses.

The invention is based on the idea that at least a part of the flame retardant used is first mixed into the fibrous raw material, after which it is ground to a desired fineness with a grinder which produces a grinding effect.

More specifically, the method according to the invention is mainly characterized by what is set forth in the characterizing part of claim 1.

The insulating material according to the invention is in turn characterized by what is set forth in the characterizing part of claim 9.

20

The asphalt or the like additive according to the invention is characterized by what is set forth in the characterizing part of claim 16.

According to the present invention, a fibrillated fiber product is prepared. , by grinding a suitable cellulosic or lignocellulosic feedstock as described below. The cheapest product is obtained by defibering waste paper, but the method is also suitable for making products directly from wood or unused pulp / paper. The waste paper may be wood-containing, i.e., paper that essentially contains only mechanical pulp, it may be wood-free, i.e., paper that contains substantially chemical pulp, or it may be a combination of these, such as LWC paper, which consists primarily of mechanical pulp. mixed with chemical pulp for reinforcement pulp. The waste paper may further contain or be substantially free of fillers and pigments.

6 95401

All of the above raw materials are also referred to in this invention as "fibrous raw material". The term "paper" includes a variety of papers, cartons, paperboards and sheets, typically having a basis weight ranging from 5 to 50 g / m2.

In a first preferred embodiment of the invention, in which a thermal insulation material is made from waste paper, a paper which consists at least 10 mainly of lignocellulosic (wood-containing) raw material is particularly suitable as a fibrous raw material. An example is the newsprint used. According to another preferred embodiment of the invention, in which, for example, an asphalt additive is prepared, the fibrous raw material which is particularly suitable is coated paper which, in addition to pulp, contains mineral fillers such as kaolin and / or talc. This type of paper is, for example, archival-grade writing papers, magazine papers, brochure papers, etc. After grinding, the product contains about 1 to 50% of kaolin, talc or similar mineral filler in the paper.

The fibrous raw material is ground to the desired fineness. By "desired fineness" is meant herein the breaking up of the fibrous raw material into smaller pieces. The size of the parts varies depending on the application. Thus, in the above-mentioned first preferred embodiment of the invention, the raw material is broken up into flakes of about 0.1 to 50 mm, preferably about 1 to 10 mm. In another embodiment of the invention, the raw material is broken down into considerably smaller particles, typically about 0.01 to 10 mm, preferably about 0.1 to 5 mm.

It is essential for grinding that it has an abrasive effect which results in the fibrillation of the fibers, resulting in a fluff-like product.

35 Thus, for example, plate and conical grinders and similar grinders with rotating grinding discs or blades are suitable grinders. Particularly preferably, the refiners are provided with grooved or serrated blades. As mentioned below, in a particularly preferred embodiment, grooved blades with grooves about 5 mm deep and brushes 3 to 5 mm high are used for grinding waste paper. Grooved blades can provide a product with a lower density than, e.g., toothed blades. The grinder used has a typical blade clearance of the order of 0.1 to 0.5 mm when grinding waste paper.

In the present invention, it has been found that flame retardants such as borax, boric acid, soda ash, urea, alkali metal salts of phosphoric acid, etc. can also be mixed into the pulp to be ground with the plate and cone grinders, if these are anhydrous or low crystalline forms. Particularly preferably, borax, soda or a combination thereof is used as the flame retardant. The flame retardants preferably consist of salts present with at least five - preferably ten - crystal water molecules as well as anhydrous or low crystalline water. An essential part of the crystalline water of said salts ·: leaves at a temperature above 30 ° to 120 ° C.

By "fire retardant" is meant reducing the flammability of a material, i.e., making the material at least substantially non-combustible and non-smoky.

The flame retardant effect of dry-mixed substances is not as great as that of substances containing water of crystallization. Therefore, in the first embodiment of the invention, in which a material suitable for thermal insulation is produced, it has been found advantageous to divide the material into two parts: dry and water-containing water. Thus, a portion - preferably 1/4 to 1/2 - of the flame retardants is introduced into the fibrous material before grinding as anhydrous and a portion - preferably 1/2 to 3/4 - as anhydrous after grinding.

If all the flame retardants are dry blended in connection with the fiber powder, a larger amount of flame retardant is required to provide initial fire protection for the material. In addition, it should be noted that not all the flame retardant material required for thermal insulation can be dry blended to the size of the fiber group, as the non-clogging of typical grooved blades cannot be guaranteed. Thus, it has been found that e.g. anhydrous borax can be added to the fibers only about 8% by weight of the fibers before grinding to keep the blades clean and not clogged. There are, of course, 10 different types of blades in use, but this note applies to blades with a groove of about 5 mm and a brush of 3 to 5 mm, which have been found to best defiber dry waste paper. The advantage of this alternative is reflected in the fact that such blades produce an insulation with a density of 30 kg / m3, while the insulation produced with 15 toothed blades or a hammer mill has a density of about 36 kg / m3.

In general, the upper limit for borax or the like flame retardant to be added anhydrous is about 10 to 15% by weight of the fibers.

When grinding, it is advantageous to mix other materials with the material, in particular one which grinds itself. Thus, in addition to or as an aid to flame retardants, other anhydrous and aqueous salts are preferably used to attach other materials to the fiber.

The procedure according to the invention achieves e.g. The following advantages: 30 - part of the flame retardant can be better distributed in the fibers. j among.

a plate grinder or conical grinder with grooved blades or serrated blades may be used, the dry material subsequently wetting 1. when 35 crystalline water is attracted, it expands and binds the fibers together, allowing a non-settling structure, - dry well-dispersed crystalline water-free but 95401 9 other desired additives.

The last note here refers in particular to 5 activated carbons.

According to the present invention, the elimination of radon disadvantages can advantageously be taken into account. In addition to thermal insulation, buildings have increasingly come into contact with radon gas insulation as tightness 10 increases. According to the invention, when carrying out the insulation of the subfloor of a building, it is advantageous to use activated carbon among the thermal insulation, because it binds radon gas for such a long time that the radioactivity of the radon has been reduced to negligible. It is preferred that the activated carbon be as evenly distributed as possible in order to have the best possible statistical potential for radon gas sequestration.

It is preferred to use 1 to 20% by weight of activated carbon, especially 1 to 5 to 20% by weight of the fibers, and 2 to 8% by weight of the inorganic substance which subsequently binds dry crystal water, all of which are mixed with the material before grinding. After grinding, the flame retardants containing water of crystallization can be mixed in a manner known per se.

25

Due to the non-settling structure, the thermal insulation according to the invention can also be used to insulate vertical walls, e.g. by blowing plant fiber insulation into the wall space.

30

Example l

Vegetable fiber products suitable for thermal insulation were made from recycled paper, which mainly consisted of newsprint-35 paper. The paper was first torn into coarse strips, after which 2-8% borax in anhydrous form was mixed into the paper material. The mixture was ground in a plate mill mix with grooved 10 95401 blades to a relatively coarse pulp flake with fiber flake sizes of about 1-5 mm. The fluff was then mixed with crystalline borax 12-20% by weight of the fibers.

5

For comparison, a pulp crumb was prepared to which all borax was added in crystalline form after grinding.

In our experiments, it has been found that dry-imported finely powdered flame retardants subsequently bound crystalline water as an IT wall, and therefore the vertical compression of the insulating products was only about 5 to 20% of that of the corresponding insulator in which the aqueous material was mixed into the pulp after grinding.

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Claims (18)

A method for producing at least a substantially non-combustible product from a fibrous raw material, the method comprising: 5. grinding the fibrous raw material to a desired fineness and - mixing a flame retardant, characterized in that - grinding is performed in a grinder with grooved blades to effect fibrillation; capable of binding water of crystallization and present in both aqueous and non-crystalline forms, and - 1/4 to 1/2 of the flame retardant is introduced into the fibrous material in anhydrous form before grinding. 15 Process according to Claim 1, characterized in that borax, soda or a combination thereof is used as the flame retardant. Method according to Claim 1, characterized in that the grinding is carried out with a plate or cone grinder. A method according to any one of claims 1 to 3, characterized in that 1/2 to 3/4 of the flame retardant 2? is introduced into the fibrous material as an aqueous crystal after grinding. A method according to claim 1, characterized in that other salts, anhydrous and aqueous, are used as an additive or as an aid to flame retardants to attach other materials to the fiber. A method according to claim 1, characterized in that at most about 10 to 15, preferably at most about 8% by weight of anhydrous flame retardant is mixed with the fibrous material. b .. · 12 95401 Process according to Claim 1, characterized in that activated carbon is ground between 1 and 20% by weight of the fibers with the anhydrous material. Use of the method according to claim 1 for the production of thermal insulation materials or additives for asphalt or similar hot-applied coatings. Thermal insulation material, characterized in that it is produced according to claim 1. Thermal insulation material according to Claim 9, characterized in that the flame retardants consist of salts which are present with at least five molecules of water of crystallization as well as with or without anhydrous crystals. Thermal insulation material according to Claim 9 or 10, characterized in that the salts for fire protection are such that a substantial part of their crystal water is discharged at temperatures above 30 ° C and below 120 ° C. 11 95401 Thermal insulation material according to Claim 9, characterized in that it contains 25 to 20% by weight of ground activated carbon of fibers. • Thermal insulation material according to Claim 9, characterized in that it contains, in addition to the salts for fire protection, other salts in the form of anhydrous and aqueous crystals which are capable of attaching other materials to the fiber. Thermal insulation material according to Claim 9, characterized in that it comprises waste paper of about 0.1 to 50 mm, preferably about 1 to 10 mm, broken down into flakes mixed with borax, soda or mixtures thereof. 13 95401 Thermal insulation material according to Claim 14, characterized in that the waste paper fibers are at least mainly derived from wood-containing recovered paper. An additive for asphalt and similar hot-applied pavements, characterized in that it is prepared in accordance with claim 1. Additive according to Claim 16, characterized in that the fibrous raw material consists essentially of plant fibers ground to a particle size of at least about 0.01 to 10 mm, preferably about 0.1 to 5 mm, from a mineral filler-containing material. paper. Filler according to Claim 16, characterized in that it contains about 1 to 50% of kaolin and / or talc. • · 14 95401