DE102004039941A1 - Wetting agent for impregnating resins - Google Patents

Abstract

The invention relates to an impregnating resin of melamine-formaldehyde resins, which contains as wetting agent one or more glycol ethers of the following structural formula DOLLAR A RO (C¶2¶H¶4¶O) ¶n¶H DOLLAR A, where DOLLAR AR = branched C¶ 5¶- to C¶15¶-alkyl and DOLLAR A n = 2 to 10, DOLLAR A and the use of glycol ethers as wetting agents for impregnating resins.

Description

The invention relates to an impregnating resin of melamine-formaldehyde resins, which as wetting agent one or more glycol ethers of the following structural formula RO (C ₂ H ₂ O) _n H contains, where
R = branched C ₅ - to C ₁₅ -alkyl and
n = 2 to 10,
and the use of glycol ethers as wetting agents for impregnating resins.

at the impregnation For example, papers with impregnating resins become nonionic Surfactants used as an aid. These have a positive effect the network behavior of the resin particles, in which they by lowering the surface tension the rapid and uniform diffusion accelerate the resin particles into the fibers.

One Disadvantage of the use of surfactants is the occurring foaming, which, for example, has a time-inhibiting effect on the impregnation process. The Operating speed of the impregnating machine must the foam development of the particular surfactant can be adjusted.

When Wetting agent for Resins in the prior art, ethoxylated fatty alcohols and alkylphenol ethoxylates, used in an amount of 0.2 to 0.6 wt .-% based on the resin solution are used (for example DE-A 41 17 841 and DE-A 199 54 189).

since However, it has long been known that alkylphenol ethoxylates are biologically are degradable and aquatic, as well as potential endocrine Possess effectiveness. In animal experiments could as consequences of the influence of alkylphenol ethoxylates infertility and malformations, as well Cancer can be detected on reproductive organs.

by virtue of These findings have been the use of alkylphenol ethoxylates in their main areas of application such as personal care and detergent industry. In smaller industries in which the Alkylphenolethoxylate used only as an aid but these are still important today.

The Object of the present invention was therefore, more environmentally friendly Auxiliary for aminoplast resins which have comparable qualities to the alkylphenol ethoxylates. Furthermore, the object was to show wetting agents for impregnating resins, in whose Use in comparison to the prior art, a reduced foaming, in particular, no foaming occurs.

Surprisingly, it has been found that impregnating resins made from melamine-formaldehyde resins which, as wetting agents, comprise one or more glycol ethers of the following structural formula RO (C ₂ H ₄ O) _n H contain, where
R = branched C ₅ - to C ₁₅ - alkyl and
n = 2 to 10,
particularly suitable for the production of aminoplast resin films and films for coating wood-based materials.

The impregnating resins according to the invention are well biodegradable and have no aquatoxicity and no endocrine activity.

Advantageous are used as wetting agents glycol ethers with a focus at n = 4 to 8, in particular at a center of gravity at n = 6 used. The number of ethoxy units is the center of gravity the ethoxy units distribution indicated. It is in the Usually around broad distributions, so that at one of the focal points of n = 6 some molecules even with n = 2 or 3 and others with n = 12 or 13 may be present.

The radical R is a branched C ₅ - to C ₁₅ -alkyl, ie a branched saturated hydrocarbon having 5 to 15 carbon atoms.

For example the radical R is a branched propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, pentyl, Isopentyl, neopentyl, tert-pentyl, hexyl, 2-methylpentyl, heptyl, 2-propylheptyl, octyl, 2-ethylhexyl, isooctyl, nonyl, isononyl, Decyl, isodecyl, undecyl, dodecyl, tridecyl, isotridecyl or tetradecyl, wherein the alkyl chain may be branched at any position can. (The above names isooctyl, isononyl, isodecyl and Isotridecyl are Trivial names and come from the after Oxosynthesis obtained alcohols - cf. to Ullmann's Encyclopedia of Industrial Chemistry, 5th Edition, Vol. A 1, pages 290 to 293, as well as Vol. A 10, pages 284 and 285.)

Simple or multiple branches are possible. The respective branches preferably consist of C _m H _{2m + 1} groups with m greater than or equal to 2.

The radical R is advantageously a branched C ₈ - to C ₁₂ -alkyl.

• – mit 1 C₂H₅-Gruppe verzweigtes C₆- bis C₁₀-Alkyl;
• – mit 1 C₃H₇-Gruppe verzweigtes C₅- bis C₉-Alkyl;
• - mit 2 C₂H₅-Gruppen oder 1 C₄H₉-Gruppe verzweigtes C₄- bis C₈-Alkyl;
• – mit 1 C₂H₅-Gruppe und 1 C₃H₇-Gruppe oder mit C₅H₁₁-Gruppe verzweigtes C₄- bis C₇-Alkyl;
• – mit 3 C₂H₅-Gruppen oder 2 C₃H₇-Gruppen oder 1 C₂H₅-Gruppe und 1 C₄H₉-Gruppe verzweigtes C₄- bis C₆-Alkyl;
• – mit 2 C₂H₅-Gruppen und 1 C₃H₇-Gruppe oder 1 C₃H₇-Gruppe und 1 C₄H₉-Gruppe verzweigtes C₄- bis C₅-Alkyl;
• – mit 4 C₂H₅-Gruppen oder 1 C₂H₅-Gruppe und 2 C₃H₇-Gruppen verzweigtes C₄-Alkyl;

wobei n = 6 besonders bevorzugt ist.In particular, the radical R is a

• - C ₆ - to C ₁₀ -alkyl branched with 1 C ₂ H ₅ group;
• - C ₅ - to C ₉ -alkyl branched with 1 C ₃ H ₇ -group;
• - C ₄ - to C ₈ -alkyl branched with 2 C ₂ H ₅ groups or 1 C ₄ H ₉ group;
• - C ₄ - to C ₇ -alkyl branched with 1 C ₂ H ₅ -group and 1 C ₃ H ₇ -group or with C ₅ H ₁₁ -group;
• - branched C ₄ - to C ₆ -alkyl with 3 C ₂ H ₅ groups or 2 C ₃ H ₇ groups or 1 C ₂ H ₅ group and 1 C ₄ H ₉ group;
• - branched C ₄ - to C ₅ -alkyl with 2 C ₂ H ₅ groups and 1 C ₃ H ₇ group or 1 C ₃ H ₇ group and 1 C ₄ H ₉ group;
• - with 4 C ₂ H ₅ groups or 1 C ₂ H ₅ group and 2 C ₃ H ₇ groups branched C ₄ alkyl;

where n = 6 is particularly preferred.

Especially Preferably, the radical R is a single ethyl or propyl branched Nonyl, octyl, heptyl or hexyl.

Most preferably, the branching consists of a C ₃ H ₇ group, in particular the radical R is 2-propylheptyl and advantageously n = 6.

In the suitability of a molecule as an adjuvant, the ratio of hydrophobic (residue R) to hydrophilic groups (ethoxy groups) is a crucial factor. Thus, a comparable effect on the net behavior of the resin particles is to be expected if molecules are used whose ratio of the hydrophobic to the hydrophilic molecule portion corresponds to that of the glycol ethers used in the invention, but their respective hydrophobic and hydrophilic molecular structure twice (for example, with R = C ₂₀ alkyl and n = 12) or three times (for example with R = C ₃₀ alkyl and n = 18) is as large as that of the glycol ethers used in the invention. This comparable effect is expected only up to a certain molecular size, since too large molecules make it difficult to diffuse quickly.

As a wetting agent it is also possible to use a mixture of the glycol ethers used according to the invention and alcohols known in the prior art. The mixing ratio of glycol ethers to alcohol is usually 90:10 to 30:70, especially 80:20 to 40:60. As alcohols can advantageously be used C ₇ - to C ₁₂ -alkyl alcohols, which are preferably linear or optionally methyl-branched.

The Wetting agent is usually in an amount of 0.05 to 1 wt .-% based on the resin solution, i. impregnating, used. Preference is given to an amount of from 0.1 to 0.7% by weight, in particular 0.2 to 0.5 wt.% Used.

In the resin solution, the aminoplast resin is usually present at 40 to 70 wt .-%, in particular 50 to 60 wt.%. Suitable crosslinkable aminoplastic resins are all resins known to the person skilled in the art, in particular melamine-urea-formaldehyde and melamine-formaldehyde resins or mixtures thereof. These resins may be partially or completely etherified with alcohols, preferably C ₁ -C ₄ -alcohols, in particular methanol or ethanol. Preference is given to using etherified and unetherified melamine-urea-formaldehyde and melamine-formaldehyde resins or mixtures thereof, in particular etherified and unetherified melamine-formaldehyde resins.

the impregnating resin according to the invention can Professional known adjuvants and additives are added, for example Urea, caprolactam, phenyldiglycol, butanediol, saccarose, as well as hardener and catalysts.

The Way, like the impregnation liquor to melamine resin impregnates be further processed and how the coating of wood materials with these impregnates takes place, is known in the art.

The impregnating resins according to the invention Accordingly, they are advantageous to aminoplast resin films or films for the Coating of wood-based materials further processed.

The innovative impregnating resins have good adhesion, improved gloss, high blackness, and low cracking. Foaming could be compared be significantly reduced to the prior art.

The invention further relates to the use of glycol ethers of the following structural formula RO (C ₂ H ₄ O) _n H, in which
R = branched C ₅ - to C ₁₅ - alkyl
n = 2 to 10,
as wetting agent for aminoplast resins, in particular impregnating resins.

Example:

Table 1: Wetting agent

100 parts of a commercial melamine-formaldehyde impregnating resin with a ratio of melamine to formaldehyde of about 1: 1.6 and a solids content of about 60% with 7.1 parts of water, with 0.3 parts of hardener (for example, SO ₂ buffered amines) and mixed with 0.3 parts of wetting agent (Example 1 to 4).

The turbidity time was 305 seconds for all impregnating resins. There was a white and a black decorative paper with the five different impregnating resins according to DE 199 54 189 impregnated.

Table 2: Impregnating liquor

The Decorative paper was at 190 ° C and 20 kp for 35 minutes pressed on an HDF plate. The data of the surface evaluation are shown in Table 3.

Table 3: Surface evaluation

regulations for the Application testing:

hardening

The Goodness of hardening is through 16-hour Action of a 0.2N hydrochloric acid, which is stained with 0.004 wt .-% rhodamine B solution on the coated Chipboard determined. With good hardening the surface does not become through the acid attacked. The strenght the attack leaves based on the strength assess the red color.

Evaluation:

• 0 = no attack
• 1 = pale pink color
• 2 = distinct red color
• 3 = strong red color
• 4 = strong red color with slight surface swelling
• 5 = strong red color with strong surface swelling
• 6 = destroyed Surface.

shine

The Gloss measurement according to DIN 67 580 by reflection measurement of a Light beam at the incident angle of 20 °. The shine is even better The higher is the percentage of reflected light in%.

unity

The closed nature or porosity of the coated chipboard surface serves to assess the sensitivity to dirt. The surface to be tested is rubbed in with black shoe polish and on closing with a rag cleaned again. The remaining in the pores shoe polish allows an assessment of the closed nature of the surfaces.

• 0 = porenfrei
• 1 = vereinzelte Poren
• 2 = wenige Poren
• 3 = häufige Poren
• 4 = viele offene Stellen
• 5 = sehr viele offene Stellen
• 6 = keine Geschlossenheit.

The assessment of the surface closure is carried out in the following stages:

• 0 = free of pores
• 1 = isolated pores
• 2 = few pores
• 3 = frequent pores
• 4 = many vacancies
• 5 = a lot of vacancies
• 6 = no closure.

crack resistance

• 0 = keine Risse
• 1 = vereinzelte kleine Risse
• 2 = wenige Risse
• 3 = mäßige Risse
• 4 = häufige Risse
• 5 = viele Risse
• 6 = totale Rissbildung.

The crack resistance of a surface is determined according to DIN 53 799. The coated chipboard is stored over a period of 24 h at 70 ° C in a convection oven. The drying process causes shrinkage stresses which lead to cracking in the surfaces. An intensification of the test can be achieved by increasing the drying temperature or by drilling the surface (notch effect). Cracking is assessed according to the following scale:

• 0 = no cracks
• 1 = isolated small cracks
• 2 = few cracks
• 3 = moderate cracks
• 4 = frequent cracks
• 5 = many cracks
• 6 = total cracking.

blackness

The Degree of blackness is measured according to D 3265 with a Tint Tester 527 with brightness measuring head Tint sensor. The measuring range includes 0-99.99 brightness units, where zero is the lowest brightness level (absolutely black). For values> 0.8 already a clear grayness visible.

To Calibration of the device with a standard, the specimen becomes three times measured and the mean indicated as Schwarzgrad.

yellowing

In order to determine the degree of thermal resistance of the resin, the yellowing of the surface is determined with a heatable stamp under pressure. The stamp of the tester is pressed at 225 ° C with 5 N / mm ² on the surface to be tested. The degree of yellowing is graded on a scale of 0-6.

Evaluation:

• 0 = no yellowing
• 1 = very slight yellowing
• 2 = visible discoloration
• 3 = moderately strong discoloration
• 4 = strong brown color
• 5 = very strong browning
• 6 = dark brown area

Tabelle 5: Oberflächenspannung

To test the surface tension, the following impregnating resins were investigated: Table 4: impregnating resins

Table 5: Surface tension

• 0 = kein Schaum
• 1 = vereinzelter Schaum, der sich sofort wieder löst
• 2 = sehr geringe Schaumbildung
• 3 = geringe Schaumbildung
• 4 = mäßige Schaumbildung
• 5 = starke Schaumbildung
• 6 = sehr starke Schaumbildung

The foaming was evaluated in the preparation of the impregnating liquor with a scale of 1 to 6.

• 0 = no foam
• 1 = isolated foam, which dissolves immediately
• 2 = very little foaming
• 3 = low foaming
• 4 = moderate foaming
• 5 = strong foaming
• 6 = very strong foaming

Table 6: Foaming

Claims (10)

Impregnating resin of melamine-formaldehyde resins containing as wetting agent one or more glycol ethers of the following structural formula RO (C ₂ H ₄ O) _n H wherein R = branched C ₅ - to C ₁₅ -alkyl and n = 2 to 10. impregnating resin according to claim 1, wherein n = 4 to 8. The impregnating resin according to claim 1 or 2, wherein the radical R is a branched C ₈ - to C ₁₂ -alkyl. The impregnating resin according to claims 1 to 3, wherein the respective branches consist of (C _m H _{2m + 1} ) groups and m is greater than or equal to 2. The impregnating resin according to claims 1 to 4, wherein the radical R is a C ₆ - to C ₁₀ -alkyl branched with 1 C ₂ H ₅ group; - C ₅ - to C ₉ -alkyl branched with 1 C ₃ H ₇ -group; - C ₅ - to C ₈ -alkyl branched with 2 C ₂ H ₅ groups or 1 C ₄ H ₉ group; - C ₄ - to C ₇ -alkyl branched with 1 C ₂ H ₅ -group and 1 C ₃ H ₇ -group or with 1 C ₅ H ₁₁ -group; - branched C ₄ - to C ₆ -alkyl with 3 C ₂ H ₅ groups or 2 C ₃ H ₇ groups or 1 C ₂ H ₅ group and 1 C ₄ H ₉ group; - branched C ₄ - to C ₅ -alkyl with 2 C ₂ H ₅ groups and 1 C ₃ H ₇ group or 1 C ₃ H ₇ group and 1 C ₄ H ₉ group; - with 4 C ₂ H ₅ groups or 1 C ₂ H ₅ group and 2 C ₃ H ₇ groups branched C ₄ alkyl; is. impregnating resin according to the claims 1 to 5, wherein the radical R is an ethyl- or propyl-branched nonyl, octyl, Heptyl or hexyl. impregnating resin according to the claims 1 to 6, wherein the radical R is 2-propylheptyl. impregnating resin according to the claims 1 to 7, where n = 6. impregnating resin according to the claims 1 to 8, in which 0.05 to 1 wt .-% wetting agent based on the impregnating resin. Use of glycol ethers of the following structural formula RO (C ₂ H ₄ O) _n H, where R = branched C ₅ - to C ₁₅ -alkyl and n = 2 to 10 as a wetting agent wetting agent.