DE2034208A1 - Waterproofing chipboard and cardboard - by incorporating paraffin hydrocarbons - Google Patents

Abstract

Hydrophobicising agent for materials based on wood, glass, flax, glass fibre, sugar cane residues, cellulose fibres, etc., and other materials which swell on exposure to moisture, and for cardboard, chipboard, etc. comprises a mixture of solid 16-40C paraffin hydrocarbons with a content of n- and isoalkanes of at least 30%, together with natural and/or synthetic hydrocarbon resins. The hydrocarbon resins may be balsam resin, tall oil resin, coumarone/indene resin, polyterpenes or synthetic petroleum resins with a mol. wt of 200-1800 and an iodine number of 0-250. The mixture may be applied as a dispersion, soln. or hot melt. The products are useful as building boards and furniture parts, etc., and for cardboards for packaging meat, fish, fruit, etc. in cold store.

Description

Water repellant and anti-swelling agent for chipboard and molded parts The invention relates to a water repellent and swelling protection agent for chipboard and molded parts, which are based on wood, flax, sugar cane residues or similar substances that swell in water are made.

Chipboard is manufactured and used in large numbers today as a starting material for the production of furniture, prefabricated houses, interior fittings or Caravan. In addition, it is possible to use molded parts in basically the same way with certain profiles.

For the gluing of the raw material, e.g. the wood chips, find as Binder glues based on thermosetting Kunxtharson use, essentially either urea / formaldehyde glue or phenol / formaldehyde glue. In addition to that Binding agents are regularly added to paraffins as water repellants, and Usually in the form of aqueous dispersions, but occasionally also in the form a melt. The addition of paraffins is used Waterproofing of the material and thus to improve the swelling behavior. As the chipboard from substances swellable in water, see B. Hardwood and softwood chips the panels will swell unexpectedly when they come into contact with water The swelling behavior can be decisively improved by adding paraffins so that certain limit values regarding the thickness swelling (e.g. maximum 6 % after 2 hours soaking in water), the transverse tensile strength, the flexural strength etc. can be switched on. The protruding material properties are according to determined according to DIN standards 52361, 52362, 52364 and 52365.

The amount of paraffin added to the raw material, e.g. the wood chips is primarily based on the desired maximum swelling value and the type the raw material used, the swelling capacity also depends on the type of wood and depends on the chip shape. Average is the amount of paraffin used, based on absolutely dry chip, at about 0.11 to 0.8% by weight.

These amounts of water repellant required are therefore relative high and it would therefore be urgently desired to find a remedy that is already at gives the same protection against swelling at lower concentrations. Furthermore lie the swelling values that can be achieved are still relatively high; for example the swelling value after 2 hours Q2 with the addition of 0.5% paraffins about 5%. It exists there is a great need for a swelling protection and water repellent agent, which at the same Concentration at significantly lower swelling values and thus at a more water-resistant one Product leads.

To solve the above problem, the invention is a water repellent and swelling inhibitors for chipboard and Pormpressteile of those specified Art proposed, which has a content of paraffinic hydrocarbons and is characterized in that it contains C16 to C40 paraffin hydrocarbons in addition to liquid and / or solid with a content of n- and iso-alkanes of at least 90% by weight, also natural and / or contains synthetic hydrocarbon resins.

While the natural and synthetic hydrocarbon resins or On the basis of tests carried out, their mixtures are seen as unsatisfactory swelling protection agents have proven, it was surprisingly found that the mixtures according to the invention Significantly lower swelling values result than due to the content of the two Components would have been expected purely arithmetically, i.e. additively. It is true watched beneficial effect theoretically not fully clarified, but it is conceivable that the paraffin hydrocarbons are used as wetting and penetrating agents serve for the hydrocarbon resins used, their creep and network properties at the temperatures prevailing inside the chipboard during the pressing process from approx. 100 to 11000 insufficient for the most complete possible wetting of the chips are. The paraffinic hydrocarbons used according to the invention therefore do not serve only as a waterproofing agent but also as a solvent for the relatively high molecular weight hydrocarbon resins in the paraffin hydrocarbons used they are aliphatics with an average carbon number of 16 to 40. These paraffin hydrocarbons can be mixtures of cyclic with straight and branched compounds, however, the content of n- and iso-alkanes should be at least 30 Gew.g, since it was rounded that with the inventive The mean swelling values that can be achieved decrease with increasing n-paraffin content. The molecular weights the preferred paraffinic hydrocarbons range from about 230 to 460, which corresponds to a boiling range at normal pressure of about 280 to 480 ° C. It can are liquid anyway i.e. paraffinic oils, as well as solid ones Paraffinic hydrocarbons act, their freezing points usually around 25 to 650C, in particular 30 to 550C.

As hydrocarbon resins are both natural and synthetic Products and mixtures of both groups are suitable.

In particular, root resins and balsam resins are used as natural resins and tall oil resins in question. On the other hand, there are also polyterpenes and indene / coumarone resins useful. Particularly preferred are synthetic petroleum hares, which in larger Extent can be obtained from the distillation products of crude oil processing. For Their production is made using a starting material consisting of low molecular weight Hydrocarbons, mainly from alkenes, diolefins and dienes consists. These monomers are in the presence of a suitable catalyst, preferably a Lewis acid such as A1C13, polymerized to polyolefin resins, which are are aliphatic compounds. Depending on their degree of polymerization, these have resins have a weakly polar to apolar character. The average molecular weights are in the range from 200 to 1,800, preferably around 00 to 1,500. The iodine number These synthetic resins can range between 0 and 250 and is preferably about 100 to 220, i.e. it is usually still partially unsaturated polymers.

The hydrophobizing and swelling protection agents according to the invention are produced by mixing the ingredients in a suitable weight ratio, the particular mixing process used is not of critical importance. The weight ratio of paraffinic hydrocarbons to hydrocarbon resin can range from 95: 5 to 5:95, but is preferably about 60:40 up to 30:70, since in the latter range usually optimal results are achieved will.

The swelling protection agent can be in the form of the inherently liquid or Molten mixture either added to the glue dispersion and in this way be introduced into the raw material for chipboard manufacture, or the agent can be separated from the glue dispersion before or

can then be worked directly into the chip material.

On the other hand, it is also possible to use the swelling protection agent in water su dispergis a he dissolve it in a suitable solvent and then shape it continue to be used in an emulsion or solution. For the production of aqueous emulsions the agents according to the invention are preferably suitable emulsifiers or dispersants added, which are cation-active, e.g. suitable ammonium salts, anion-active, e.g. sodium or potassium soaps or non-ionic, such as ethylene oxide condensation products, to know his.

Suitable solvents are aliphatic and aromatic hydrocarbons as well as chlorinated hydrocarbons.

There is a further possibility for processing the swelling protection agent in that this is carried out on a solid, finely divided carrier, s.B. Sawdust or wood flour 1 applies and then this relatively highly dispersed solid product with thoroughly mixed with the raw materials for chipboard production.

The respectively chosen working method for the incorporation of the quellaite ice is not critical of me as long as it is ensured that the agent is in the raw material is so well distributed that as complete a coating as possible of the individual particles is achieved when the material is pressed.

The following examples are intended to explain the invention in more detail serve, to which the patent application is not limited.

Example 1 Sanded wood chipboard (thickness 19 mm, density 645 g / 1), 60% of which consisted of deciduous wood and 40% of coniferous wood Help of 8.5% urea / formaldehyde glue (Kaurit 385 from Badische Anilin- und soda factories, Ludwigshafen) at a press temperature of 1600C in the usual way manufactured. The swelling protection agents to be examined in each case were in the form of 40% strengths aqueous dispersions mixed with the glue.

The finished panels were then made within 6 hours Squares with an edge length of 25 mm cut out and for 2 hours with one Temperature of 20 + 1 ° C immersed in water, whereupon the percentage increase in Plate thickness was measured as the swelling value Q2.

This determination of the source value corresponds to DIN 52364. The The following quantities for the swelling protection agent are in each case on an absolutely dry basis Chip related.

The freezing points given for the paraffinic hydrocarbons are determined on the rotating thermometer.

1. Chipboard without swelling inhibitor Q2 / 15.3% 2. Chipboard with additive of 0.5% paraffin hydrocarbons (solidification point: 52/54 ° C oil content: 2.5% n-paraffin content: 65%) 5.1% 3. Chipboard with the addition of 0.5% polyolefin resin (Ring and ball softening point: 100 ° C) 10.8% 4. Paraffin-based oil1 (boiling range: 280-310 ° C n- and iso-paraffin content: approx. 35%) 15.0% 5. Chipboard with the addition of 0.5% of a mixture of 50% polyolefin resin according to 3.

+ 50% paraffin hydrocarbons according to 2. 2.9% 6. Chipboard with Addition of 0.5% of a mixture of 50% polyolefin resin according to 3.

+ 50% paraffin hydrocarbons (freezing point: 36-38 ° C oil content: 3.1% n-paraffin content: approx. 95%) 2.2% 7. Clamping plate with the addition of 0.5% of a Mixture of 50% polyolefin resin according to 3 + 50% paraffin-based oil according to 4 3.5 % A comparison of the results of experiments 2 and 3 with the experiment 5 clearly shows that by replacing the conventionally used paraffinic hydrocarbons by an equal amount of the anti-swelling agent according to the invention Polyolefin resin and paraffinic hydrocarbons share a very significant reduction of the swelling value during one application of the polyolefin harses alone does not lead to a swelling value which is sufficient for practice. The experiments show In addition, all other things being equal, the source value increases with diminishing n-paraffin content of the swelling protection agent according to the invention falls. The best results are observed with the paraffin obtained from light spindle oil slack (experiment 6), while the value for the paraffin obtained from heavy spindle oil slack (experiment 5) is in the middle. However, even when using a paraffinic oil (Experiment 7) is a very considerable improvement over paraffin alone (Experiment 8) achieved.

Example 2 Under the conditions of Example 1, another Series of tests carried out to determine what effect on the achievable Swelling protection is the content of the Faraffin hydrocarbon mixture used in the anti-swelling agent at has n-alkanes. The test results are compiled in Table 1 below. It is clear that the swelling protection is better, the higher the content of the paraffin content on n-alkanes. On the other hand, the influence of the chain length of the n-alkane component is probably only of minor importance for source protection, but the The number of carbon atoms is practically limited by the fact that both the flash point as well as the onset of boiling do not lie too low; accordingly, the minimum number of carbon atoms should be of the alkanes are about 16.

The results in Table I also show that that the binary anti-swelling agents made from hydrocarbon resin and paraffin hydrocarbons Significantly lower swelling values result than swelling ingredients which only contain resin or contain paraffin. If only a certain source value is not exceeded may be, a significantly lower amount of swelling protection agent according to the invention is sufficient, while, on the other hand, hitherto hardly attainable low swelling values for the same Concentrations can be achieved as they are conventionally already used have found.

Table 1 Vers.No. % Polyolefin -% paraffin carbons - Q2 in% resin according to hydrogen a) 0.5% experiment 3 b) 0.2% hydrophobing agent on atro-chip a) b) 7 55 45 paraffin according to 2.5 4.6 vers. 2 8 55 45 paraffin according to 1.9 4.1 vers. 6 9 (comparison) 55 45 Paraffin flow 5.0 11.0 (EP .: approx. 54 ° C oil content: approx. 20% n-alkanes approx. 10%) 10 55 45 Paraffin obtained 2.1 4.0 from urea adduct (EP .: 31 ° C oil content: 21% n-alkanes approx. 90%) 11 55 45 paraffin-based 3.2 5.1 oil, acc. Vers. 4 12 55 45 naphthenic oil 3.4 5.4 (boiling range 20 to 260 ° C) n- and iso-alkanes approx. 35% 3 (comparison) 100 0 10.8 -2 (comparison) 0 100 paraffin acc. 5.1 -vers. 2 Example 3 Another series of tests after the general The procedure of Example 1 was carried out to examine what influence the weight ratio of hydrocarbon resin to paraffinic hydrocarbons in the water repellent according to the invention has on the swelling protection. From the in the following table II summarized test results can be seen, that the optimum is around 55% by weight of resin and 45% by weight of paraffin and that opposite the individual components a clear general proportional improvement in a weight ratio from HC resin to paraffin in the range of 40:60 to 70:30 is achieved. Here, too, falls on that the content of the paraffin hydrocarbon mixtures of n- and iso-alkanes has an influence on the attainable source value.

Table II Vers. No.% polyolefin-% paraffin-carbon Q2 in% at Resin according to hydrogen 0.5% hydrophobic test 3 bierungsmittel on atro-Span 2 (Comparison) 0 100 paraffin according to verse 2 13 10 90 dto.

30 70 dto.

15 40 60 as above 3.8 16 45 55 as above 3.3 17 50 5Q as above 2.9 7 55 45 as above. 2.5 18 60 40 as above 3.4 19 70 30 as above 3.5 20 90 10 as above 5.6 3 (comparison) 100 0 10.8 21 40 60 paraffin-based 3.6 oil, gen. Vers. 4 22 50 50 dto. 3,5 11 55 45 dto. 3.2 23 60 40 same 3.3 24 65 35 same 3.6 25 70 30 same 3.8

Claims (7)

Patent claims 1. Hydrophobing and swelling protection agents for on Base of wood, flax, sugar cane residues or similar ones swelling in water Chipboard or molded parts made from substances with a content of paraffinic hydrocarbons, characterized in that it contains liquid and / or solid C16 to C40 paraffinic hydrocarbons with a content of n- and iso-alkanes of at least about 30% by weight, also natural and / or contains synthetic hydrocarbon resins. 2. Means according to claim 1, characterized in that the synthetic Hydrocarbon resins have a molecular weight in the range from about 200 to 1,800, preferably 400 to 1,500, and an iodine number of 0 to 250, preferably 100 to 220. 3. Means naoh claim i, characterized in that it is natural Resins contains root resins and / or balsam resins and / or tall oil resins. 4. Means according to claims 1 to 3, characterized in that the weight ratio of hydrocarbon resins to paraffinic hydrocarbons in the range from 95: 5 to 5:95, preferably in the range from 40:60 to 70:30. 5. Means according to claims 1 to 4, characterized in that it dispersed in a liquid medium, preferably in water, or in a solvent is resolved. 6. Composition according to claim 5, characterized in that it is used for dispersion contains an emulsifier or dispersant in water. 7. Means according to Claims 1 to II, characterized in that it by applying it to a solid support, preferably wood flour, in finely divided Form.