FI64174C - FRAME STEERING PANEL FOR THERMOFORMING PANELS AND FRAME RELEASE PANELS - Google Patents

Description

* | · 4Μ ~ · Ι ΓΒΐ rt1x ANNOUNCEMENT s Λ * η λ LJ * 'UTLÄG G N! N GS SKRI FT »41/4 • • gSj c (45) i ato.:·..'I IyJ3 ^" Ö8 '¥ 251/02, c 08 J 7/16, (51) Kv.ik./. nt.cr? 2 21 J Ί / 16, D 21 H 3/22 FINLAND — FINLAND WP «en« lh4kemus - Patentansöknln g 77325- (22) Application date— Ansöknlngsdag i-.lC.77 (23) Starting date - Giltighetsdag 31.10 * 77 (41) Become Public - Bllvit offentllg 12. C'5.7'3

National Board of Patents and Registration .... ...,, ,, ..,

• (44) Date of issue and date of publication—, Q

Patent- och registerstyreisen Ansökan utlagd och utl.skrlften publlcerad 30.06.o3 (32) (33) (31) Requested privilege — Begird prior'tet 11.11.76

Luxembourg (LU) 76--72 (71) PRB SA, avenue de Broqueville, 12, 1150 Brussels, Belgium-Belgium (BE) (72) Georges J. Cloetens, Brussels, Leonard F. Livens, Heppen, Belgium-Belgium ( BE) (7 ^) Oy Jalo Ant-Wuorinen Ab (5I) Method for the production of thermoformed panels and use of panels made according to the method from a raw material consisting of modified lignocellulosic fibers.

The production of panels from a lignocellulosic fibrous base by a wet, semi-wet or dry process is well known. It is also known to add plastic, in particular phenol-type resin, to the pulp used to make the panels.

The nature of the raw materials, i.e. the chemical composition and size of the fibers, can cause production difficulties in the manufacture of the panels. Separation of water from the pulp, a process which is preferably carried out by filtration and which is necessary for the manufacture of panels and which must take place in a relatively short time, is one of the most important factors for the economics of the process. The filterability, which means the rate at which water is removed from the pulp by filtration in a panel production plant, can be varied with the various additives added during pulp production, and most additives generally do not change the filterability in the preferred direction.

In one particular field, unsatisfactory filterability properties are particularly evident. It has been found that the filterability deteriorates as the number of lignocellulose-based fibers obtained from non-refined material, such as fibers consisting mainly of recovered fibers such as waste paper or crude vegetable fibers, increases.

Another disadvantage associated with the addition of additives, and in particular phenolic resins, to the pulp is the consequent heavy contamination of water, mainly with phenolic compounds and salts.

CH patent 378,665 mentions e.g. that a pulp made from a material containing about 20% waste paper gives such poor filterability properties and a significant deterioration in productivity. The said patent proposes a mechanical treatment, which, however, is limited to dry-treated waste paper and which does not reduce water contamination due to conventional additives.

The invention therefore relates to a process for the production of thermoplastic panels from a lignocellulosic material of non-refined material by a semi-wet process, by means of which the above-mentioned disadvantages can be avoided.

The invention provides a method of making thermoplastic panels from lignocellulosic fibers, wherein the aqueous suspension of fibers forming a conventional pulp for making panels is grafted with at least a portion of the fibers with an olefinic monomer in the presence of a redox catalyst system below pH U,

Filtration, drying and panel shaping are performed to produce thermoplastic panels in a conventional manner. It has been found that it is very easy to filter the pulp after the grafting treatment according to the invention.

During grafting, part of the monomer homopolymerizes. This homopolymer fraction does not adversely affect the quality of the product and remains in the mass from which the water is separated by filtration.

The water separated by filtration is essentially uncontaminated and can be recycled directly back several times without any treatment.

3 64174

The method is suitable for all types of lignocellulosic fibers, but is particularly advantageous when applied to a raw material consisting of recovered fibers, in particular waste paper, for example old newspapers and raw vegetable fibers such as bamboo, bagasse, reed waste, etc.

Under said grafting conditions, i.e. at a pH below k and in the presence of a redox-catalytic system, a relatively large part of the monomer is homopolymerized, but grafting also occurs partly with cellulose (polysaccharide) and lignin. The choice of pH and catalytic system used allows for optimal distribution of the polymer attached to the fibers, i.e., grafted into cellulose and lignin, and the polymer precipitated as a homopolymer alone to achieve good cohesion between the fibers. It appears that the grafted polymer ensures good adhesion of said homopolymer to the fibers, while the presence of the homopolymer in the fibers provides good inter-bonding of the fibers during the thermoforming of the product.

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Furthermore, a well-known fact in polymer chemistry is that the average molecular weight of the polymer is of great importance in view of the mechanical properties of the product. The above process conditions are critical to obtain satisfactory properties of the thermoformable product.

The polymerization conditions must therefore be closely monitored. It has been found that when the pH is above k, only the use of specially treated or refined fibers gives satisfactory quality properties.

The product obtained under the above conditions contains 0.5 to 20% of graft polymer, i.e. 0 to 10% of graft cellulose and 0 to 10% of graft lignin and 10 to 30% of homopolymer. The products are not sticky.

The most interesting monomers in terms of low cost reagents are styrene, methyl methacrylate and methyl acrylate. However, other monomers such as acrylonitrile and ethyl acrylate may prove equally suitable.

When pressure is used, vinyl monomers such as vinyl chloride or vinylidene chloride can also be used. These reagents are interesting because they impart 1-life properties to the products thus formed »

Other chemical and physical grafting conditions that depend on the selected monomer are conventional and are described in FR Patent 2,276, ^ 23, GB Patent 1,011, ^ 31, U.S. Patents 3,330,686 and 3,533,725, and DE Application Application No. 1.5 ^ 6, ^ 68. .

64174

The most preferred catalytic system, both in terms of efficiency and low cost, is the redox system Fe / f ^ C ^.

When waste paper is used as a graftable cellulosic base, the pulp will always contain a sufficient amount of iron.

When using a redox system, the Fe / H 2 O 2 content should be at least 0.00001 to 0.01% of the total weight of the suspension and liquid, the H 2 O 2 content should be 0.0001 to 0.1%.

The total amount of fibers relative to the total amount of suspension and liquid should be 0.5 to 8%.

The ratio between the monomers and the lignocellulosic base should preferably be from 5 to 0%, in particular from 9 to 30%. Said upper limit is mainly due to economic reasons and the desire to preserve the fibrous nature of the product and, of course, also the reactivity of the monomer which affects the amount of grafted or homopolymerized monomer.

The best results are obtained for styrene with values of 15-20% and for methyl methacrylate with values of 25-30%.

The grafting is generally carried out at a temperature of 10 to 100 ° C, preferably 30 to 70 ° C and in particular 50 to 60 ° C.

After filtration, the dried mass, preferably with a wet content of less than 1%, is pressed for a short time (0.5 to 2 minutes) at an average pressure of about 10 to 100 bar, in particular 30 to 80 bar and a temperature of 160 to 220 ° C.

It is also possible to use a mixture of fibers treated according to the invention with conventional fibers, i.e. refined and / or non-refined ungrafted fibers, the presence of grafted fibers according to the invention greatly improving the filterability properties of the final product.

With the method according to the invention, it is possible to achieve "Canadian Freeness" values which, according to the Scandinavian standard method SCAN-C19: 65 (corresponds to the Canadian standard method CPPA C 1:62), are more than 500, starting from a CF value of less than 500.

The process according to the invention makes it possible to produce thermoplastic panels from raw materials with CF values of less than 500, of which 20 to 100% are derived from non-refined fibers, e.g. waste paper, in an economical manner so that the quality of the panels is comparable to refined material. the quality of the panels produced. They can be used to make the lining of molded objects such as car doors.

The invention is explained in more detail in the following examples, which are intended to illustrate the invention.

These partial percentages are percentages, unless otherwise stated, by weight-present 1 e j a.

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Example 1 The purpose of this example is to compare the pulps prepared in the usual way with the pulps according to the invention.

Suspensions of 8% fibers of various origins in water were prepared and heated to 50-60 ° C. 0.1% FeSO 4 and 1% from 100% # 2 ° 2 were then added to the cash register. reagents and then monomer was added. The reaction was complete after one hour and the results are shown in Table I.

Example 2

The effect of different parameters on the proportion of grafted polymer was investigated on a laboratory scale.

10 g of cellulose (bleached Kraft paper or newspapers) was added to a 500 ml Erlenmeyer flask together with 250 ml of water. To this was added 5 ml of FeCl 3, 0.1 m and 5 ml of 3%. H ^ O ^.

It was found that grafting also occurs in the presence of lignin, although in this case a considerable amount of homopolymer may be formed.

The monomer yield was close to 100% in each case.

The results of this experiment are reported in Table II. The percentage of homopolymer is determined by extraction with dichloroethane or benzene.

Example 3

Different process factors were studied.

To a 2-liter reactor equipped with a lid and a stirrer were added 1.5 liters of water and 30 g of grafted cellulose, which had been comminuted in advance.

The required amount of Fe 2 O 3 in the form of 0.1 M FeCl 3 solution and 3% Bta was then added. 11 ^ 02 ^ ta (10 til- $).

After completion of the reaction, it was filtered and dried.

The percentage of homopolymer was determined by extraction with dichloroethane or benzene.

The following Table III shows the results obtained by grafting methyl methacrylate onto newsprint.

Example k

The effect of different raw materials on the process in methyl methacrylate grafting was studied by treating 60 g of product in a 2 liter reactor. The initiator used was a FeSO 4 / H 2 O system, the pH was adjusted with H 2 O 2, and the temperature was 60 ° C, with a reaction time of 60 minutes. The results are shown in Table IV.

Example 5

An experiment similar to the previous one was performed, however, this time using styrene. The results are given in Table V.

Example 6

The effect of mixtures of monomers was also studied by grafting them onto 60 g of newsprint in a 2 liter reactor. The results are shown in Table VI.

Example 7

Compositions have been prepared containing styrene as a monomer using the grafting polymer prepared under the conditions mentioned in Example 1 and comprising 8% grafting styrene and 16% styrene homopolymer together with non-grafted fibers.

Table VII shows their properties compared to a 100% ungrafted fiber preparation.

Table I According to the invention:

Ordinary Styrene MMA

Kraf t 50

Wood fibers 20

Newsprint 15 80 70

Phenolic resins 15

Polystyrene 20

Polymethyl methacrylate 50 o

Tensile strength: N / mm ^ 0 59 * K)

Moisture absorption after 2 ^ hours 27 2! 0 50

Bending modulus: N / mm2 ^ 500 6500 7000

Tensile bending strength: N / mm2 70 80 86

Compressive strength: N / mm2 ^ 5 50 55 7 64174

Table II

Cellulose Kraft Newsprint g. cellulose

Monomer MMA MMA MA MA MMA + MA

g. monomer 20 10 10 10 8 6 temperature / ° C 50 20 50 20 50 20 time / min 60 60 60 60 60 60% homopolymer 1 ^ 22 kl 39 20 25% grafted polymer ^ 8 22 3 5 20 12 MMA = methyl methacrylate MA = methyl acrylate

Table III

Λ1 Fe k 6 8 12 16 32 16 16 l6 ψΐ H 2 O 2 16 16 16 16 16 16 k 8 12 temperature / 0 ^ 30 beginning 60 end time / min 60% homopolymer 2 9 13 23 26 31 32 27 31% grafted polymer 0 32 32 21 19 13 1 ^ 18 1 ^ 64174

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Table V (styrene)

Cellulose Crude kraft Mechanical Newsprint eucalyptus pulp mg Fe 8 28 56 28 28 l68 ml H 2 O 2, 3% 15 15 15 30 30 30 pH 3 3 3 3,2 3,2 3,1 tensile strength N / mm2 l * f 16 19 21 21 bending modulus N / mm2 ^ 200 extreme bending strength N / mm2 ^ 5 moisture 2 h X ^ 1 32 11 9 9 2 * + h X 97 86 25 19 19% resin 09 10.5 25 30 30% homopolymer 10.5 6.7 10 .5 1 ^, 8% grafted cellulose - 1.7 1.3 1.9% grafted lignin - 16.6 18.2 13.3

Table VI (mixture of monomers) ml styrene 20 20 15 15 15 ml MMA - 5 5 5 ml Fe 0.1 M 10 5 0 1 2.5 ml H 2 O 2 3% 30 30 30 30 30 pH 3 3.2 3.1 3.3 3.2 tensile strength N / mm2 38 30 12 23 moisture 2h h * 22 25 28 23% resin 22 l8, * f 3 21 22.3% homopolymer 16.2 11 6.6 10 ^ grafted polymer 5.8 7, ^ 1 * + / + 12.3

Claims (11)

A method of producing thermoformable panels of lignocellulosic fibers, characterized in that in a suspension of fibers in the wick, which forms a conventional mass for the production of panels, a grafting is performed at least part of the fibers with an olefin monomer and in the presence of a redox catalytic system at a pH below 4. 2. A process according to claim 1, characterized in that the monomer used is styrene, methyl methacrylate or methyl acrylate. Process according to claim 1 or 2, characterized in that the catalytic system used is the redox-Fe / H2C> 2 system. 4. A process according to claim 3, characterized in that 0.00001-0.01% Fe and 0.0001-0.1% H 2 inoculation. Process according to any of claims 1-4, characterized in that monomers are used in an amount of 5-40% and preferably 9-30% in the ratio of the lignocellulosic base. Method according to any of claims 1-5, characterized in that the grafting is carried out at a temperature of 10-100 ° C, especially 30-70 ° C and heist 50-60 ° C. Process according to any of claims 1-6, characterized in that in the ratio of lignocellulosic pulp, 0.5-20% by weight of grafted product having the proportions 0-10% grafted cellulose and 0-10% grafted lignin and 10% -30% homopolymer. Method according to any of claims 1-7, characterized in that the fibers which have not undergone grafting are mixed with fibers which have been treated according to the grafting process. Method according to any of claims 1-8, characterized in that the pulp is dried after filtration to a moisture content of less than 1% and undergoes a short-duration pressing with an average pressure of the order of 10-100 bar and at a temperature of 160 -220 ° C. Method according to any of claims 1-9, characterized in that one starts with a mass having a