FI64130C - RAOSKIVA FOER EN BYGGNADSSKIVA PAO GIPSBASIS SOM FRAMSTAELLS ENLIGT UPPRULLNINGSFOERFARANDET - Google Patents

Description

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Wa 1 * '^ UTLAGG NI NGSSKRIFT 641 30 • tpjjg c (45) "^: ^; t;! 1 3 (51) K». »K? /Lnt.CI.3 C 04 B 31/36 ENGLISH —FINLAND (21) Ptttnttihaktinui-PKMMMAiurinc 0017) 6 (22) MakemltpUvi - AntSknlngsdag 30.05.80 '* (23) Origin — GlMghucadac 30.05.80 (41) Tullut |

Patent] · Registry Board. . ... _....._

Patent- och registerstyrelsen () utllikirtftan puUkerad 30.06.83 (32) (33) (31) Privilege requested - & «fird priorltet (71) Oy Partek Ab, 2l600 Parainen, Finland-Finland (PI) (72) Kauko Ensio Junkkarinen, Muijala, Suomi-Finland (FI) (7 * 0 Berggren Oy Ab (5 * +) Raw board made by the method of collecting gypsum-based building boards - Heavy duty for the construction of gypsum bases from fram-Stalis enligt upprullningsförfarandet

The invention relates to a raw board produced by a method of collecting a gypsum-based building board, which contains cellulose and / or waste paper fibers ground as its wet pulp carrier fibers, gypsum as a binder, and hydraulically curable cement, reinforcing fibers and additives as other ingredients.

It is known from Finnish patent application 780190 to produce a raw board made by collecting an asbestos-free gypsum-based building board, which contains 70-95% by weight of gypsum as a semi-hydrate and 30-70 ° SR (Schopper-Riegler) reinforcing and filling fibers and additives.

However, it has not been possible to produce the board with the desired capacity according to said method. The reason for this has been found to be the poor adaptability of the pulp, i.e. its tendency to behave more like a low viscosity liquid than like a supporting pulp. Its filterability is also unsatisfactory, which means that too much solids are absorbed with the water into the felt of the 2,641 30 collecting machine (Hatschek) and from there with the water out of the process. Materials adhering to the felt also shorten the life of the machine, resulting in an excessive number of downtimes.

In an attempt to eliminate said disadvantages in a different manner, it has been found that in the method according to the invention, in which a smaller amount of hydraulically curable cement, 10-30% of the total weight of its dry matter, is added to the gypsum, the desired capacity is achieved.

It has also been found that the effluent is cleaner, that the number of downtimes has decreased and that the life of the felt has increased. The pulp also has the desired supportive structure. Compared to the subject of said application 780190, the result is considerably better.

The ratios of gypsum, cement and cellulose fibers in the known boards are as follows:

It is known from Finnish patent application 762484 to use cement as 10-80% binder and gypsum as a hemihydrate, which, however, is practically completely converted to the dihydrate before the wet mass is collected into a sheet. According to the present invention, on the other hand, gypsum is the main binder. Gypsum is also present in the raw board as a hemihydrate. Only a small amount of cement, 10-30%, is used, which is therefore not actually intended to act as a binder, but is used to improve the properties of the board known from patent application 780190.

In the process of application 762484, the cellulosic fibers are not opened at all, while according to the present invention, the cellulosic fibers are opened at a temperature of 20-80 ° SR, which is of paramount importance for obtaining a good green sheet. According to the invention, a considerable amount of gypsum can be incorporated into the raw board due to the smaller amount of cement.

In the process according to BOCJOS1 of Leon's application, the hydraulic binder is mixed with the fibers, water and possibly other additives into a slurry. According to paragraph 4 of page 9 of the explanatory part of the application, for example, 641 30 3 cement or gypsum is used as the hydraulic additive. However, the present application does not state, as in the application according to the invention, that when gypsum is used as a binder, a smaller amount of cement is also used, the purpose of which is to improve the properties of the greenboard. The cellulosic fibers are ground according to application 800051 with sulphate solutions which slow down the processing, and the degree of grinding, which is not mentioned, appears to be less than the degree of grinding of 20 to 80 ° SR according to the present invention.

Swiss Patent Publication 368,740 does not disclose carrier cellulosic fibers having a degree of grinding of 20 to 80 ° SR as carrier fibers, nor reinforcing fibers up to 20% of the total dry weight of the raw board. This publication therefore focuses on a special collection method in which there is no problem with the carrier fiber. According to the publication, in addition to gypsum (requirement 3), gypsum slag cement, the amount of which is not specified, can be used as a binder. Since the cellulosic fibers are not suitably opened and gypsum slag cement is used as a binder, and therefore not in particularly small amounts to improve the properties of the board, the publication reveals the inventive idea of our application, i.e. to determine the correct degree of opening of the cellulosic fibers in relation to the smaller amount of cement used and to relate this to the amount of gypsum. In addition, gypsum slag cement has a vague composition.

German application DE-0S 2 336 220 refers to building boards produced by casting and pressing, in which case there are no problems with the collection method according to our invention. Thus, the grinding of cellulosic fibers has not been determined at all. According to the publication, gypsum is used as a binder.

In addition (claim 6), cement in an amount of less than 10%, which is less than the amount expressed in the claim of our application, can be used.

According to German application DE-0S 2 649 300, sheet-like material is produced, in particular cardboard, cardboard and building boards, in which the gypsum is in the form of a dihydrate. In particular, the method means avoiding a method (3rd p., 3 pcs.) In which the gypsum is in the form of a hemihydrate as in the raw board according to the present invention. The degree of grinding of the cellulosic fibers has also not been determined, and in Examples 1-3, pp. 6-8, which show the manufacture of building boards, various resins are used as binders. Lines 1 and 2 on page 5 of the publication show only vaguely that both organic and inorganic binders come into question in the manufacture of sheets.

In addition, when testing the finished sheets made by the method according to the invention, it has surprisingly been found that their moisture resistance, flexural strength, stiffness and surface hardness have increased more than expected. In addition, the corrosion effect has decreased as the pH of the pulp increases. These advantages have been achieved without abandoning the improved fire resistance of the boards with the use of gypsum when they are made by a collection method using ground cellulose fibers as carrier fibers.

It has been found in the experiment that the achievement of the optimum result depends to a large extent on the correct degree of opening of the pulp fiber in relation to the amount of cement in question, which in turn must be related quite precisely to the amount of gypsum.

The features of the invention appear from the following claim. According to it, the raw board contains 30-85% by weight of gypsum in the form of CaSO4 -1 / 2 H2O as a binder, 10-30% of hydraulically curable cement, 3-30% of cellulose and / or waste paper fibers opened to a degree of grinding of 20-80 ° SR, and other as ingredients reinforcing and additives to the extent indicated in the claim.

The following table shows some comparative test results. The first horizontal row shows the results obtained on the basis of the composition of the building board according to Finnish patent application 780190 and the following horizontal rows show the results obtained on the basis of the composition of the present invention.

Composition Density Flexural strength Impact strength Note.

kg / m ^ N / rnm ^ Nrrrn / mm-1. driving position. driving direction driving direction direction direction, nassa direction vast, nassa

Pulp fiber 10%

Gypsum 90% 1150-1300 10.1 20.7 3.5 5.9 Fi-hak.

780190

Flokkul. ain.n. 100 ppn

Pulp fiber 10%

Gypsum 80% 1250-1350 12.3 25.4 2.1 4.1

Cement 10%

Flokkul. ain.n. 100 ppn

Pulp fiber 10%

Gypsum 70% 1320-1420 13.2 33.0 3.0 5.2

Senator 20%

Flokkul.

ain.n. 100 ppn Present —- - Present

Pulp fiber 8%. .

keksm-

Fiberglass 2% ...

to

Gypsum 50% 900 7.1 13.5 3.1 4.8

Semsntti 10%

Butter 30%

Flokkul. (Light product, e.g.

ain.n. 100 ppn ns. ship plate)

Claims (1)

6,641 30 Claim A raw board produced by the method of collecting a gypsum-based building board, which contains pulp fibers of pulp and / or waste paper as carrier fibers, gypsum as a binder, and hydraulically curable cement, reinforcing fibers and additives, characterized in that the raw material contains 30-85% hydraulically curable cement, 10-30% blast furnace slag, fly ash up to 50% diatomaceous earth, perlite, vermiculite, limestone powder, sand and similar fillings in the form of CaSO 2 or waste paper fibers, degree of grinding 20-80 ° SR 3-30% mineral fibers, glass fibers, glass, lining, slag wool, etc. "20% organic fibers: sisal, hemp, plastic fibers, etc." 20% gypsum setting retardants 0, 1-2% flocculants 200 ppm Heavy duty on the basis of gypsum based on the above-mentioned finishing properties, in the case of Malda cellulosa- och / or spreader spreader spreader, spreader spreader, splint and splice component, hydraulic spreader cement, spreader spreader and spatula, and net nozzles for heavy duty torrsubstansvikt räknat innehäller: % hydrauliskt härdnande cement 10-30% masugnsslagg, flygaska maxinalt 50% kiselgur, Perlite, vermiculite, kalkstensmjöl, sand ed fillerämne "50% cellulose- och / eller avfallspappers- fibrer, milling grade 20-80 ° SR 3-30% mineralfibrer, glasfibrer, glas-, mineral-, slaggull ed" 20% organic fiber: sisal-, hamp-, plast- fibrer ed "20% bindings for gypsum 0.1-2 f'ockni n <js.lirunen" 200 ppm l!