Paper making and fiber liberation – Processes and products – Plural fiber containing
Reexamination Certificate
2001-12-04
2004-09-21
Chin, Peter (Department: 1731)
Paper making and fiber liberation
Processes and products
Plural fiber containing
C162S157200, C162S157300, C428S221000, C428S332000, C428S337000, C428S340000
Reexamination Certificate
active
06793772
ABSTRACT:
The present invention relates to the use of melamine resin fibers and insulating materials based on melamine resin fibers and polyalkylene terephthalate fibers and processes for their production.
Insulating materials in the building construction sector, for example for the thermal and acoustic insulation of buildings and parts of buildings, are frequently produced using insulating mats based on glass or mineral fibers. It is true that these materials generally have good insulating properties, but they also have the disadvantage that they are brittle and very fragile, releasing very short fibrous fragments in certain circumstances. Consequently, they are not always easy to process into fiber mats; secondly, respirable microfibers are considered a health hazard. Furthermore, inorganic materials generally have a higher density than organic materials, which leads to heavier products and thus to higher transportation costs.
There is consequently a need for an insulating material which is based on organic fibers, which substantially equals the insulating properties of inorganic materials, which is simple to produce and which is easy to process.
DE-A 31 47 308 and EP-A 80 655 describe insulating materials composed of melamine resin fiber mats having the following properties:
a) the thickness is between 20 and 200 mm,
b) the density is between 10 and 150 g 1
−1
,
c) the DIN 52 612 thermal conductivity is less than 0.05 W m
−1
K
−1
,
d) the DIN 52 215-63 sound absorption at 2500 Hz, converted from perpendicular to stationary sound incidence, is greater than 90%,
e) the recovery capacity, measured on a 100 mm thick mat compressed to 30 mm within 2 min and held at that thickness for 24 hours, is so high that the mat, on the pressure being removed, spontaneously rebounds to a thickness of more than 80 mm and, after 6 hours, has come back to a thickness of more than 98 mm,
f) the fire behavior is so favorable that building material class B1 (low-flammable) is achieved in the DIN 4102 Part I fire test.
The melamine resins used can be melamine/formaldehyde condensation products which, as well as melamine, can contain up to 50% by weight of other thermoset-formers and, as well as formaldehyde, up to 50% by weight of other aldehydes in cocondensed form. The thermoset-formers used can be alkyl-substituted melamine, urea, urethanes, carboxamides, dicyandiamides, guanidine, sulfurylamide, sulfonamide, aliphatic amines and also phenols and its derivatives. Examples of usable aldehydes are acetaldehyde, trimethylolacetaldehyde, acrolein, benzaldehyde, furfural, glyoxal, phthalaldehyde and terephthalaldehyde. However, preference is given to unmodified melamine/formaldehyde condensation products. The insulating materials based on these melamine resin fiber mats can be used for thermal and acoustic protection of buildings and parts of buildings.
EP-A 523 485 describes condensation products obtainable by condensational mixture of a) melamine, b) substituted melamines and unsubstituted and/or substituted phenols with formaldehyde or formaldehyde-supplying compounds, a process for their production and their use for producing fibers. These condensation products are notable for improved hydrolysis stability and reduced formaldehyde emissions.
It is an object of the present invention to find novel advantageous uses for melamine resin fibers obtainable as described in EP-A-523 485, for example.
We have found that this object is achieved by a method of using modified melamine resin fibers obtainable by condensational mixture comprising
(A) from 90 to 99.9 mol % of a mixture comprising
(a) from 30 to 99.9 mol % of melamine and
(b) from 1.0 to 70 mol % of a substituted melamine of the general formula I
where X
1
, X
2
and X
3
are each selected from —NH
2
, —NHR
1
and —NR
1
R
2
, subject to the proviso that X
1
, X
2
and X
3
are not all —NH
2
, and R
1
and R
2
are independently selected from hydroxy-C
2
-C
20
-alkyl, hydroxy-C
2
-C
4
-alkyl-(oxa-C
2
-C
4
-alkyl)
n
, where n is from 1 to 5, and amino-C
2
-C
12
-alkyl, or mixtures of melamines of formula I, and
(B) from 0.1 to 10 mol %, based on (A) and (B), of a compound selected from phenols which are unsubstituted or substituted by radicals selected from C
1
-C
9
-alkyl and hydroxyl, C
1
-C
4
-alkanes substituted by two or three phenol groups, di(hydroxyphenyl) sulfones and mixtures thereof,
with formaldehyde or formaldehyde-supplying compounds in a molar ratio of melamines to formaldehyde within the range from 1:1.15 to 1:4.5, as and in thermal and/or acoustic insulating material. Suitable modified melamine resin fibers are described in EP-A 523 485, for example. The fibers can be processed into shaped thermal and/or acoustic insulation articles by customary methods known to one skilled in the art. Such methods will be described in more detail in what follows. Advantageously, the modified melamine-formaldehyde resin fibers described in EP-A 523 485 have a more textile hand than conventional melamine resin fibers. They are less brittle and do not break so easily, so that generally fewer short fibrous filaments and dust are released on processing into shaped articles, for example fiber mats. In addition, they are generally also kinder to the skin than the conventional fibers. Insulating materials based on the melamine resin fibers described in EP-A-523 485 are preferably useful for thermal and/or acoustic protection of buildings and parts of buildings. They are further useful for thermal and/or acoustic insulation in mechanical engineering, refrigeration technology, for insulating liquid- and/or gas-conducting pipes on the inside and outside of buildings, etc.
In a suitable embodiment, the aforementioned melamine resin fibers can be used together with polyalkylene terephthalate fibers. Polyalkylene terephthalate fibers which are suitable for this purpose are described in what follows.
The present invention further provides an insulating material comprising
a) from 5 to 95% by weight of melamine resin fibers,
b) from 5 to 95% by weight of polyalkylene terephthalate fibers,
and optionally
c) up to 30% by weight of further fibers, and/or
d) up to 20% by weight of additives.
Component a)
Suitable melamine resin fibers are unmodified melamine resin fibers and preferably modified melamine resin fibers and mixtures thereof.
Melamine/formaldehyde condensation products which are suitable for producing melamine resin fiber mats are described in EP-A 0 080 655, fully incorporated herein by reference. The melamine/formaldehyde condensation products may, as well as melamine, contain up to 50% by weight, preferably up to 20% by weight, of other thermoset-formers and, as well as formaldehyde, up to 50% by weight, preferably up to 20% by weight, of other aldehydes in cocondensed form.
Suitable other thermoset-formers include, for example, alkyl-substituted melamine, urea, urethanes, carboxamides, dicyandiamide, guanidine, sulfurylamide, sulfonamide, aliphatic amines and also phenol and its derivatives.
Suitable other aldehydes include, for example, acetaldehyde, trimethylolacetaldehyde, acrolein, benzaldehyde, furfural, glyoxal, phthalaldehyde and terephthalaldehyde.
The molar ratio of thermoset-formers to aldehyde is generally within the range from about 1:1.5 to about 1:4.5. If unmodified melamine/formaldehyde condensates are used, then the molar ratio is generally within the range from about 1:2.5 to about 1:3.5.
Such fibers can be produced, for example, by spinning a highly concentrated aqueous solution of a melamine-aldehyde precondensate. Such processes are described in DE-A 23 64 091, for example, and may utilize a hauler plate or a die. The fibers are predried, optionally stretched, and finally the melamine resin is cured at from about 150 to 250° C. Possible curing catalysts are customary acids, for example sulfuric acid, hydrochloric acid, acetic acid or preferably formic acid, which are added to the aqueous solution of the precondensate in amounts of from about 0.1 to 5.0% by weight. It is likewise possible to add the curing catalyst after
Berbner Heinz
Ott Karl
BASF - Aktiengesellschaft
Chin Peter
Keil & Weinkauf
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