WOOD COATING PRODUCTS CONTAINING VEGETAL-ORIGIN ANTI-OXIDANTS, AND METHODS TO MAKE THE SAME

Abstract

A wood coating composition comprising: an acrylic or polyurethane or alkid resin, or a combination thereof; a water-based solvent comprising water and a polyalcohol, or an organic solvent selected among ketones, esters, aromatic hydrocarbons as toluene, alone or in a combination; wherein the resin has a weight ratio set between 10% and 80% or between the 20% the 70%, respectively with an or the other type of solvent. The compositions include a UV-protection additive comprising polyphenols, in particular a mixture of tannins extracted from such a wood as a Fagaceae, Mimosaceae or Rosaceae wood, at a weight ratio set between 0.5% and 4% with respect to the weight of the composition. Essential requirement for the UV-protection additive to work in a water-based solvent-containing composition is that the pH is higher than a predetermined minimum value higher than 7.

Claims

1.-37. (canceled)

38. A wood coating composition, comprising: a water-based solvent comprising water and a polyalcohol, a resin selected from the group consisting of: an acrylic resin; a polyurethane resin; an alkyd resin; a combination, in particular a mixture thereof; a UV-protection additive comprising polyphenols, wherein said UV-protection additive has a weight ratio set between 0.5% and 4% with respect to said composition, wherein said resin has a weight ratio set between 10% and 80% with respect to said composition; characterized in that said composition has a pH value selected between 7 and a value higher than 7, i.e. a pH value higher than a pH minimum value higher than or equal to 7.

39. The composition according to claim 38, wherein said UV-protection additive containing complex polyphenols is a tannin.

40. The composition according to claim 39, wherein said tannin is selected from the group consisting of: a Fagaceae tree tannin; a Mimosaceae tree tannin; a Rosaceae tree tannin; a combination thereof.

41. The composition according to claim 38, wherein said additive containing complex polyphenols is a tannin derivative, or a synthetic tannin.

42. The composition according to claim 38, wherein said UV-protection additive comprise complex polyphenols having a molecular weight higher than 1000.

43. The composition according to claim 38, also containing an alkaline pH-modifier, in particular said pH-modifier is selected from the group consisting of ammonia, an amine, an alkaline or alkaline-earth hydroxide, an alkaline-earth carbonate.

44. The composition according to claim 38, wherein said pH minimum value is 7.5, in particular said pH minimum value is 8.

45. The composition according to claim 38, wherein said pH value is set between said pH minimum value and 11, in particular between said pH minimum value and 10.

46. The composition according to claim 38, wherein said resin is selected between an anionic resin, a non-ionic resin, a combination thereof.

47. The composition according to claim 38, wherein said weight ratio of said resin is set between 20% and 50%.

48. The composition according to claim 38, wherein said weight ratio of said resin is set between 50% and 80%.

49. The composition according to claim 38, wherein said polyalcohol has a weight ratio set between 1% and 6% with respect to said composition.

50. The composition according to claim 49, wherein said polyalcohol is selected from the group consisting of: butylene glycol, dibutylene glycol, propylene glycol n-butyl ether, methoxypropanol, diethylene glycol.

51. A method for making a wood coating composition, comprising the steps of: prearranging an amount of a water-based solvent comprising water and a polyalcohol; prearranging an amount of a resin selected from the group consisting of: an acrylic resin; a polyurethane resin; an alkid resin; a combination, in particular a mixture thereof; introducing said amount of said water-based solvent and said amount of said resin into a container; stirring said amount of said water-based solvent and said amount of said resin within said container until a homogeneous mixture is obtained; comparing a pH value of said mixture with a predetermined pH minimum value higher than or equal to 7; if said pH value of said mixture is lower than said predetermined minimum pH value, adding an amount of an alkaline pH modifier until said pH value of said mixture has reached a value at least as high as said predetermined minimum pH value; adding an amount of a UV-protection additive comprising complex polyphenols, obtaining said composition, wherein said UV-protection additive has a weight ratio set between 0.5% and 4% with respect to said composition, wherein said resin has a weight ratio set between 10% and 80% with respect to said composition.

52. The method according to claim 51, wherein said additive containing complex polyphenols is selected from the group consisting of: a tannin, wherein said tannin is selected from the group consisting of: a Fagaceae tree tannin; a Mimosaceae tree tannin; a Rosaceae tree tannin; a combination thereof; a tannin derivative; a synthetic tannin.

53. The method according to claim 51, wherein said pH-modifier is selected from the group consisting of ammonia, an amine, an alkaline or alkaline-earth hydroxide, an alkaline-earth carbonate.

54. The method according to claim 51, wherein said pH minimum value is 7.5, in particular said pH minimum value is 8.

55. The method according to claim 51, wherein said pH value is set between said pH minimum value and 10.

56. The method according to claim 51, wherein said polyalcohol has a weight ratio set between 1% and 6% with respect to said composition.

57. The method according to claim 51, wherein said polyalcohol is selected from the group consisting of: butylene glycol, dibutylene glycol, propylene glycol n-butyl ether, methoxypropanol, diethylene glycol.

58. A wood coating composition, comprising: an organic solvent selected from the group consisting of: a ketone; an ester; an aromatic hydrocarbon selected from the group consisting of: toluene, a xylene and a combination thereof; a combination thereof, a resin selected from the group consisting of: an acrylic resin; a polyurethane resin; an alkid resin; a nitrocellulose resin; a combination thereof; a UV-protection additive, wherein said UV-protection additive has a weight ratio set between 0.5% and 4% with respect to said composition wherein said resin has a weight ratio set between 20% and 70% with respect to said composition, characterized in that said UV-protection additive comprises a mixture of polyphenols deriving from aqueous extract of predetermined woods.

59. The composition according to claim 58, wherein said additive containing complex polyphenols is a tannin.

60. The composition according to claim 58, wherein said predetermined woods are selected from the group consisting of: a Fagaceae tree; a Mimosaceae tree; a Rosaceae tree; a combination thereof.

61. The composition according to claim 58, wherein said UV-protection additive comprise complex polyphenols having a molecular weight higher than 1000.

62. The composition according to claim 58, wherein said weight ratio of said resin is set between 10% and 70%.

63. The composition according to claim 58, wherein said weight ratio of said resin is set between 40% and 70%.

64. The composition according to claim 58, also comprising an alcohol, with a weight ratio at most of 5% with respect to said composition, in particular said alcohol is selected from the group consisting of: isopropyl alcohol, butyl alcohol, ethyl alcohol.

Description

EXAMPLE 1—COMPOSITIONS CONTAINING A WATER-BASED SOLVENT, AN ANIONIC ACRYLIC RESIN, AND MIMOSACEAE TANNIN

[0125] 10-80 grams of a polyglycol mixture have been added to 600-800 grams of a water-soluble anionic acrylic resin, under stirring. When the obtained mass appeared to be homogeneous, an amount between 0.5 and 2% of Mimosaceae tannin was added. During the preparation, strict care was taken in maintaining the pH of the samples between 7.5 and 10, which in some instances was obtained by using an alkaline pH modifier, in amounts up to 12 g.

EXAMPLE 2—COMPOSITIONS CONTAINING A WATER-BASED SOLVENT, AN ANIONIC ACRYLIC RESIN, AND FAGACEAE TANNIN

[0126] 40-100 grams of a polyglycol mixture have been added to 400-700 grams of a water-soluble anionic acrylic resin, under stirring. When the obtained mass appeared to be homogeneous, an amount between 0.5% and 2% of Fagaceae tannin was added. During the preparation, strict care was taken in maintaining the pH of the samples between 7.5 and 10, which in some instances was obtained by using an alkaline pH modifier, in amounts up to 14 g.

EXAMPLE 3—COMPOSITIONS CONTAINING A WATER-BASED SOLVENT, A NON-IONIC ACRYLIC RESIN, AND ROSACEAE TANNIN

[0127] 20-80 grams of a polyglycol mixture have been added to 500-800 grams of a water-soluble non-ionic acrylic resin, under stirring. When the obtained mass appeared to be homogeneous, an amount between 0.5 and 2% of Rosaceae tannin was added. During the preparation, strict care was taken in maintaining the pH of the samples between 7.5 and 10, which in some instances was obtained by using an alkaline pH modifier, in amounts up to 15 g.

EXAMPLE 4—COMPOSITIONS CONTAINING A WATER-BASED SOLVENT, A NON-IONIC ACRYLIC RESIN, AND FAGACEAE TANNIN

[0128] 20-80 grams of a polyglycol mixture have been added to 450-750 grams of a water-soluble non-ionic acrylic resin, under stirring. When the obtained mass appeared to be homogeneous, an amount between 0.5% and 2% of Fagaceae tannin was added. During the preparation, strict care was taken in maintaining the pH of the samples between 7.5 and 10, which in some instances was obtained by using an alkaline pH modifier, in amounts up to 14 g.

EXAMPLE 5—COMPOSITIONS CONTAINING A WATER-BASED SOLVENT, AN ALKID RESIN, AND FAGACEAE TANNIN

[0129] 40-100 grams of a polyglycol mixture have been added to 400-700 grams of a water-soluble alkid resin, under stirring. When the obtained mass appeared to be homogeneous, an amount between 0.5% and 2% of Fagaceae tannin was added. During the preparation, strict care was taken in maintaining the pH of the samples between 7.5 and 10, which in some instances was obtained by using an alkaline pH modifier, in amounts up to 10 g.

EXAMPLE 6—COMPOSITIONS CONTAINING A WATER-BASED SOLVENT, A POLYURETHANE RESIN, AND FAGACEAE TANNIN

[0130] 30-80 grams of a polyglycol mixture have been added to 500-700 grams of a water-soluble polyurethane resin, under stirring. When the obtained mass appeared to be homogeneous, an amount between 0.5% and 2% of Fagaceae tannin was added. During the preparation, strict care was taken in maintaining the pH of the samples between 7.5 and 10, which in some instances was obtained by using an alkaline pH modifier, in amounts up to 11 g.

EXAMPLE 7—COMPOSITIONS CONTAINING A FULLY ORGANIC SOLVENT, AN ALKID RESIN, AND MIMOSACEAE TANNIN

[0131] 40-80 grams of a hydrocarbon mixture have been added to 400-600 grams of an alkid resin, under stirring. When the obtained mass appeared to be homogeneous, an amount between 1% and 2% of Mimosaceae tannin was added. The Mimosaceae tannin had previously been dissolved in an organic solvent, in order to allow a full dissolution in the sample being formed.

EXAMPLE 8—COMPOSITIONS CONTAINING A FULLY ORGANIC SOLVENT, A POLYURETHANE RESIN, AND ROSACEAE TANNIN

[0132] 60-120 grams of a mixture of carbonyl compounds have been added to 500-700 grams of a polyurethane resin, under stirring. When the obtained mass appeared to be homogeneous, an amount between 1.5% and 3% of Rosaceae tannin was added. The Rosaceae tannin had previously been dissolved in an organic solvent, in order to allow a full dissolution in the sample being formed.

EXAMPLE 9—COMPOSITIONS CONTAINING A FULLY ORGANIC SOLVENT, AN ACRYLIC RESIN, AND FAGACEAE TANNIN

[0133] 100-150 grams of a mixture of carboxylic compounds have been added to 500-700 grams of an acrylic resin, under stirring. When the obtained mass appeared to be homogeneous, an amount between 1% and 3% of a Fagaceae tannin was added. The Fagaceae tannin had previously been dissolved in an organic solvent, in order to allow a full dissolution in the sample being formed.

[0134] Characterization a of an Exemplary Wood Varnish Product

[0135] Protecting the Colour from the Effects of UV Radiations

[0136] Tests have been made according to EN ISO 11507:2007 to evaluate the colour stability of four different finishing varnishes on durmast wood and pine wood samples. The finishing varnishes contained four different additives, among which two additives according to the invention, i.e.: [0137] a Fagaceae tannin; [0138] a Mimosaceae tannin,
and two known UV-protection additives, i.e.: [0139] Tinuvin 5151, a traditional UV-absorber; [0140] Nanobyk 3840, a more recent UV-absorber.

[0141] The coated wood samples were maintained at constant temperature and humidity during a stabilization time according to the above EN standard. Afterwards, a test was carried out consisting in alternately exposing the samples to UV-B radiation and rising the relative humidity, during an overall test time of two weeks. The colour was spectrophotometrically determined before and after the test. Table 3 shows the result of these measurements, in the case of the varnishes containing a tannin, as average values obtained by a same group of compositions.

TABLE-US-00003 TABLE 3 Durmast wood samples 1) Compositions of Example 1 Δeab = 1.54 2) Compositions of Example 2 Δeab = 1.05 3) Composition containing Tinuvin 5151 Δeab = 2.84 4) Composition containing Nanobyk 3840 Δeab = 1.12 Pinewood samples 5) Compositions of Example 1 Δeab = 2.07 6) Compositions of Example 2 Δeab = 1.31 7) Composition containing Tinuvin 5151 Δeab = 3.32 8) Composition containing Nanobyk 3840 Δeab = 1.64,

[0142] where Δeab is the difference of the light emission of a sample irradiated between before and after the treatment briefly described above. More in detail, this difference is defined as the square root of the difference of the squares of the absorbance measured according to three axes, i.e. a bright/dark axis, a yellow/blue axis and a green/red axis. The lower Δeab, the higher is the colour preservation power of the varnish.

[0143] According to the results of Table 3, the Fagaceae tannin is in any case more effective than the reference conventional additives, regardless of the coated wood substrate. An anti-oxidant effect globally comparable with that of the conventional additives is determined also for Mimosaceae tannin, depending in this case on the coated wood substrate.

[0144] Moreover, even in this case, the Fagaceae tannin turned out to be the most effective as an additive for obtaining a coating having an anti-oxidant activity.

[0145] Even if in the examples more extensive reference is made to varnishes, the results obtained from the text can be extended to coating products in general, e.g. to paint products based on the compositions according to the invention, also containing pigments.

[0146] The foregoing description of exemplary embodiments and specific examples of the invention will so fully reveal the invention according to the conceptual point of view, so that others, by applying current knowledge, will be able to modify and/or adapt for various applications such embodiment without further research and without parting from the invention, and, accordingly, it is to be understood that such adaptations and modifications will have to be considered as equivalent to the specific embodiment and examples. The means and the materials to put into practice the different functions described herein could have a different nature without, for this reason, departing from the field of the invention. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation.