U.S. patent application number 09/751008 was filed with the patent office on 2002-09-05 for parting agent for an isocyanate wood binder.
Invention is credited to Lu, Li-Mei, Mente, Donald C., Peters, David D., Schaefer, Anthony G., Wilson, Joe C..
Application Number | 20020123641 09/751008 |
Document ID | / |
Family ID | 25020069 |
Filed Date | 2002-09-05 |
United States Patent
Application |
20020123641 |
Kind Code |
A1 |
Mente, Donald C. ; et
al. |
September 5, 2002 |
Parting agent for an isocyanate wood binder
Abstract
There is disclosed a parting agent comprising the reaction
product of an isocyanate compound and an isocyanate-reactive
compound of the general structure R--(ao).sub.n--Y wherein: R is a
hydrophobic group containing alkyl, alkaryl, polyaryl, or siloxane
moieties; (ao) is an alkylene oxide or mixture of alkylene oxides
such as ethylene oxide, propylene oxide, butylene oxide, and
mixtures thereof; n is about 1 to about 25; and Y represents a
monofunctional isocyanate-reactive group. There is also disclosed
the processes that may be utilized to produce the parting
agent.
Inventors: |
Mente, Donald C.; (Grosse
Ile, MI) ; Lu, Li-Mei; (Canton, MI) ; Peters,
David D.; (Wyandotte, MI) ; Wilson, Joe C.;
(Woodhaven, MI) ; Schaefer, Anthony G.;
(Wyandotte, MI) |
Correspondence
Address: |
Fernando A. Borrego
BASF Corporation Legal Department
1609 Biddle Avenue
Wyandotte
MI
48192
US
|
Family ID: |
25020069 |
Appl. No.: |
09/751008 |
Filed: |
December 29, 2000 |
Current U.S.
Class: |
560/25 |
Current CPC
Class: |
C08L 75/04 20130101;
C08G 18/6492 20130101; C08L 97/02 20130101; C08G 18/289 20130101;
C08L 97/02 20130101; C08G 18/7671 20130101; C08G 18/283 20130101;
C08G 2125/00 20130101 |
Class at
Publication: |
560/25 |
International
Class: |
C08G 018/30 |
Claims
We claim:
1. A parting agent, comprising the reaction product of an
isocyanate compound and an isocyanate-reactive compound of the
general structure R--(ao).sub.n--Y wherein R is a hydrophobic group
containing alkyl, alkaryl, polyaryl, or siloxane moieties, wherein
the alkyl moieties comprise straight chain or branched hydrocarbons
with 6 or more carbon atoms, the alkaryl moieties comprise
monoalkyl, dialkyl, or trialkyl substituted aromatic hydrocarbons
with 9 or more carbon atoms, the polyaryl moieties comprise a
polyphenyl structure that is either alkyl substituted or
unsubstituted, and the siloxane moieties comprise a trisiloxane or
higher polysiloxane; (ao) is an alkylene oxide or mixture of
alkylene oxides selected from the group consisting of ethylene
oxide, propylene oxide, butylene oxide, and mixtures thereof; n is
from 1 to 25; and Y represents a monofunctional isocyanate-reactive
group.
2. The parting agent according to claim 1, wherein the isocyanate
compound is a polyisocyanate compound.
3. The parting agent according to claim 1, wherein the isocyanate
compound comprises a diphenylmethane diisocyanate isomer, R
comprises an alkaryl, and Y is a hydroxyl group
4. The parting agent according to claim 3, wherein n is from about
1 to about 10.
5. The parting agent according to claim 1, wherein Y is either a
hydroxyl group or a monoalkyl amino group.
6. The parting agent according to claim 1, wherein the isocyanate
compound is an aromatic isocyanate compound.
7. The parting agent according to claim 1, wherein the isocyanate
compound comprises a diphenylmethane diisocyanate (MDI) isomer
selected from the group consisting of 2,2'-MDI, 2,4'-MDI, 4,4'-MDI,
and mixtures thereof.
8. The parting agent according to claim 1, wherein the isocyanate
compound comprises a diphenylmethane diisocyanate isomer, R
comprises a polyaryl, and Y is a hydroxyl group.
9. The parting agent according to claim 8, wherein n is from about
1 to about 10.
10. The parting agent according to claim 1, wherein the isocyanate
compound comprises a diphenylmethane diisocyanate isomer, R
comprises a siloxane moiety, and Y is a hydroxyl group.
11. The parting agent according to claim 10, wherein n is from
about 1 to about 10.
12. The parting agent according to claim 1, further including the
addition of a synergist selected from the group consisting of
C.sub.1-C.sub.4 N-alkylpyrrolidones, gamma-butyrolactone, and
mixtures thereof.
13. The parting agent according to claim 1, wherein the isocyanate
compound comprises a diphenylmethane diisocyanate isomer, R
comprises a polyalkaryl, and Y is a hydroxyl group.
14. The parting agent according to claim 13, wherein n is from
about 1 to about 10.
15. A process for producing a parting agent, comprising the steps
of: a) providing an isocyanate compound and an isocyanate-reactive
compound of the general structure R--(ao).sub.n--Y wherein, R is a
hydrophobic group containing alkyl, alkaryl, polyaryl, or siloxane
moieties and wherein the alkyl moieties comprise straight chain or
branched hydrocarbons with 6 or more carbon atoms, the alkaryl
moieties comprise monoalkyl, dialkyl, or trialkyl substituted
aromatic hydrocarbons with 9 or more carbon atoms, the polyaryl
moieties comprise a polyphenyl structure that is either alkyl
substituted or unsubstituted, and the siloxane moieties comprise a
trisiloxane or higher polysiloxane wherein the alkyl moieties
comprise straight chain or branched hydrocarbons with 6 or more
carbon atoms, the alkaryl moieties comprise monoalkyl, dialkyl, or
trialkyl substituted aromatic hydrocarbons with 9 or more carbon
atoms, the polyaryl moieties comprise a polyphenyl structure that
is either alkyl substituted or unsubstituted, and the siloxane
moieties comprise a trisiloxane or higher polysiloxane; (ao) is an
alkylene oxide or mixture of alkylene oxides selected from the
group consisting of ethylene oxide, propylene oxide, butylene
oxide, and mixtures thereof; n is from about 1 to about 25; and Y
represents a monofunctional isocyanate-reactive group; b) reacting
the isocyanate compound and the isocyanate reactive compound for a
time sufficient to react out substantially all of the isocyanate
groups.
16. The process according to claim 15, wherein the isocyanate
compound and the isocyanate-reactive compound are provided in
stoichiometrically equivalent amounts.
17. The process according to claim 15, comprising providing the
isocyanate-reactive compound wherein Y is a hydroxyl group.
18. The process according to claim 15, comprising providing an
aromatic isocyanate compound.
19. The parting agent according to claim 15, wherein step a)
comprises providing a diphenylmethane diisocyanate isomer and an
isocyanate-reactive compound wherein R comprises an alkaryl and Y
is a hydroxyl group
20. The process according to claim 15, wherein step a) comprises
providing a diphenylmethane diisocyanate isomer and an
isocyanate-reactive compound wherein R comprises a polyaryl and Y
is a hydroxyl group.
21. The process according to claim 15, wherein step a) comprises
providing a diphenylmethane diisocyanate isomer and an
isocyanate-reactive compound wherein R comprises a siloxane moiety
and Y is a hydroxyl group.
22. The process according to claim 15, wherein step a) comprises
providing a diphenylmethane diisocyanate isomer and an
isocyanate-reactive compound wherein R comprises a polyalkaryl and
Y is a hydroxyl group.
23. A process for producing a parting agent, comprising the steps
of: a) providing an isocyanate compound and an isocyanate-reactive
compound of the general structure R(ao).sub.nY in
stoichiometrically equivalent amounts; wherein R is a hydrophobic
group containing alkyl, alkaryl, polyaryl, or siloxane moieties and
wherein the alkyl moieties comprise straight chain or branched
hydrocarbons with 6 or more carbon atoms, the alkaryl moieties
comprise monoalkyl, dialkyl, or trialkyl substituted aromatic
hydrocarbons with 9 or more carbon atoms, the polyaryl moieties
comprise a polyphenyl structure that is either alkyl substituted or
unsubstituted, and the siloxane moieties comprise a trisiloxane or
higher polysiloxane wherein the alkyl moieties comprise straight
chain or branched hydrocarbons with 6 or more carbon atoms, the
alkaryl moieties comprise monoalkyl, dialkyl, or trialkyl
substituted aromatic hydrocarbons with 9 or more carbon atoms, the
polyaryl moieties comprise a polyphenyl structure that is either
alkyl substituted or unsubstituted, and the siloxane moieties
comprise a trisiloxane or higher polysiloxane; (ao) is an alkylene
oxide or mixture of alkylene oxides selected from the group
consisting of ethylene oxide, propylene oxide, butylene oxide, and
mixtures thereof; n is from about 1 to about 25; and Y represents a
monofunctional isocyanate-reactive group b) reacting the isocyanate
compound and the isocyanate reactive-compound at a first
temperature until the isocyanate number is at an intermediate
level; c) thereafter, adding a second charge of an isocyanate
compound; and d) reacting the second charge of isocyanate compound
and the isocyanate reactive-compound at a second temperature higher
than the first temperature for a time sufficient to react
substantially all of the isocyanate groups.
24. The process according to claim 23, wherein step c) comprises
adding the second charge of an isocyanate compound in an amount of
about 1 to 10 weight percent, based on the weight of the isocyanate
compound charged in step a).
25. The process according to claim 23, wherein step a) comprises
providing a polyisocyanate and an isocyanate-reactive compound
wherein Y comprises a hydroxyl group.
26. A process for producing a parting agent, comprising the steps
of: a) providing an isocyanate compound and an isocyanate-reactive
compound of general structure R(ao).sub.n--Y wherein: R is a
hydrophobic group containing alkyl, alkaryl, polyaryl, or siloxane
moieties and wherein the alkyl moieties comprise straight chain or
branched hydrocarbons with 6 or more carbon atoms, the alkaryl
moieties comprise monoalkyl, dialkyl, or trialkyl substituted
aromatic hydrocarbons with 9 or more carbon atoms, the polyaryl
moieties comprise a polyphenyl structure that is either alkyl
substituted or unsubstituted, and the siloxane moieties comprise a
trisiloxane or higher polysiloxane wherein the alkyl moieties
comprise straight chain or branched hydrocarbons with 6 or more
carbon atoms, the alkaryl moieties comprise monoalkyl, dialkyl, or
trialkyl substituted aromatic hydrocarbons with 9 or more carbon
atoms, the polyaryl moieties comprise a polyphenyl structure that
is either alkyl substituted or unsubstituted, and the siloxane
moieties comprise a trisiloxane or higher polysiloxane; (ao) is an
alkylene oxide or mixture of alkylene oxides selected from the
group consisting of ethylene oxide, propylene oxide, butylene
oxide, and mixtures thereof; n is from about 1 to about 25; and Y
represents a monofunctional isocyanate-reactive group in amounts
such that the molar ratio of the isocyanate compound to
R(ao).sub.n--Y is greater than 1:1; b) reacting the two compounds
at a first temperature until substantially all of the
R(ao).sub.n--Y has reacted; c) thereafter, reacting at a second
temperature higher than the first temperature until substantially
all of the excess isocyanate groups have reacted.
27. The process according to claim 26, wherein an allophanate
catalyst is added to the components in step a).
28. The process according to claim 26, wherein an allophanate
catalyst is added to the components after step b) and before step
c).
Description
FIELD OF THE INVENTION
[0001] The present invention relates to a parting agent for use
with isocyanate wood binder resins and the processes of producing
the parting agent. The parting agent can be used with isocyanate
wood binder resins that can optionally include synergists such as
C1 to C4 N-alkyl pyrrolidones or gamma-butyrolactone.
BACKGROUND OF THE INVENTION
[0002] A common disadvantage of the use of isocyanate binder resins
is their poor mold or press release properties, which can lead to
problems during manufacture of the lignocellulosic articles when
the mold parts or press parts stick to the articles.
[0003] To overcome the sticking, it is desirable to use a parting
agent either internally as a component of the binder resin, or
externally by applying it to the mold or press parts between runs.
External parting or release agents are less preferred because their
use involves the extra step of applying the agents to the mold or
press parts. Also it can be difficult to ensure complete coverage
of the mold or press parts by the parting agent.
[0004] It is therefore, an object of the present invention to
provide a parting agent for an isocyanate binder resin, which will
not only display the desired parting properties but will also be
compatible with the isocyanate binder resin.
SUMMARY OF THE INVENTION
[0005] There is provided according to a first embodiment of the
present invention a parting agent, comprising the reaction product
of an isocyanate compound and an isocyanate-reactive compound of
the general structure
R--(ao).sub.n--Y
[0006] wherein: R is a hydrophobic group containing alkyl, alkaryl,
polyaryl, or siloxane moieties, wherein the alkyl moieties comprise
straight chain or branched hydrocarbons with 6 or more carbon
atoms, the alkaryl moieties comprise monoalkyl, dialkyl, or
trialkyl substituted aromatic hydrocarbons with 9 or more carbon
atoms, the polyaryl moieties comprise a polyphenyl structure that
is either alkyl substituted or unsubstituted, and the siloxane
moieties comprise a trisiloxane or higher polysiloxane; (ao) is an
alkylene oxide or mixture of alkylene oxides selected from the
group consisting of ethylene oxide, propylene oxide, butylene
oxide, and mixtures thereof; n is from 2 to 25; and Y represents a
monofunctional isocyanate-reactive group.
[0007] In a second embodiment, a process for producing a parting
agent comprises the step of providing an isocyanate compound and an
isocyanate-reactive compound of the general structure
R--(ao).sub.n--Y wherein: R is a hydrophobic group containing
alkyl, alkaryl, polyaryl, or siloxane moieties and wherein the
alkyl moieties comprise straight chain or branched hydrocarbons
with 6 or more carbon atoms, the alkaryl moieties comprise
monoalkyl, dialkyl, or trialkyl substituted aromatic hydrocarbons
with 9 or more carbon atoms, the polyaryl moieties comprise a
polyphenyl structure that is either alkyl substituted or
unsubstituted, and the siloxane moieties comprise a trisiloxane or
higher polysiloxane wherein the alkyl moieties comprise straight
chain or branched hydrocarbons with 6 or more carbon atoms, the
alkaryl moieties comprise monoalkyl, dialkyl, or trialkyl
substituted aromatic hydrocarbons with 9 or more carbon atoms, the
polyaryl moieties comprise a polyphenyl structure that is either
alkyl substituted or unsubstituted, and the siloxane moieties
comprise a trisiloxane or higher polysiloxane; (ao) is an alkylene
oxide or mixture of alkylene oxides selected from the group
consisting of ethylene oxide, propylene oxide, butylene oxide, and
mixtures thereof; n is from about 1 to about 25; and Y represents a
monofunctional isocyanate-reactive group. A second step comprises
reacting the isocyanate compound and the isocyanate reactive
compound for a time sufficient to react out substantially all of
the isocyanate groups.
[0008] In a third embodiment a process for producing a parting
agent comprises the step of providing an isocyanate compound and an
isocyanate-reactive compound of the general structure R(ao).sub.nY
in stoichiometrically equivalent amounts, wherein: R is a
hydrophobic group containing alkyl, alkaryl, polyaryl, or siloxane
moieties and wherein the alkyl moieties comprise straight chain or
branched hydrocarbons with 6 or more carbon atoms, the alkaryl
moieties comprise monoalkyl, dialkyl, or trialkyl substituted
aromatic hydrocarbons with 9 or more carbon atoms, the polyaryl
moieties comprise a polyphenyl structure that is either alkyl
substituted or unsubstituted, and the siloxane moieties comprise a
trisiloxane or higher polysiloxane wherein the alkyl moieties
comprise straight chain or branched hydrocarbons with 6 or more
carbon atoms, the alkaryl moieties comprise monoalkyl, dialkyl, or
trialkyl substituted aromatic hydrocarbons with 9 or more carbon
atoms, the polyaryl moieties comprise a polyphenyl structure that
is either alkyl substituted or unsubstituted, and the siloxane
moieties comprise a trisiloxane or higher polysiloxane; (ao) is an
alkylene oxide or mixture of alkylene oxides selected from the
group consisting of ethylene oxide, propylene oxide, butylene
oxide, and mixtures thereof; n is from about 1 to about 25; and Y
represents a monofunctional isocyanate-reactive group. The
subsequent steps comprise reacting the isocyanate compound and the
isocyanate reactive-compound at a first temperature until the
isocyanate number is at an intermediate level; thereafter, adding a
second charge of an isocyanate compound; and reacting the second
charge of isocyanate compound and the isocyanate reactive-compound
at a second temperature higher than the first temperature for a
time sufficient to react substantially all of the isocyanate
groups.
[0009] In a fourth embodiment a process for producing a parting
agent comprises the step of providing an isocyanate compound and an
isocyanate-reactive compound of general structure R(ao).sub.n--Y
wherein: R is a hydrophobic group containing alkyl, alkaryl,
polyaryl, or siloxane moieties and wherein the alkyl moieties
comprise straight chain or branched hydrocarbons with 6 or more
carbon atoms, the alkaryl moieties comprise monoalkyl, dialkyl, or
trialkyl substituted aromatic hydrocarbons with 9 or more carbon
atoms, the polyaryl moieties comprise a polyphenyl structure that
is either alkyl substituted or unsubstituted, and the siloxane
moieties comprise a trisiloxane or higher polysiloxane wherein the
alkyl moieties comprise straight chain or branched hydrocarbons
with 6 or more carbon atoms, the alkaryl moieties comprise
monoalkyl, dialkyl, or trialkyl substituted aromatic hydrocarbons
with 9 or more carbon atoms, the polyaryl moieties comprise a
polyphenyl structure that is either alkyl substituted or
unsubstituted, and the siloxane moieties comprise a trisiloxane or
higher polysiloxane; (ao) is an alkylene oxide or mixture of
alkylene oxides selected from the group consisting of ethylene
oxide, propylene oxide, butylene oxide, and mixtures thereof; n is
from about 1 to about 25; and Y represents a monofunctional
isocyanate-reactive group in amounts such that the molar ratio of
the isocyanate compound to R(ao).sub.n--Y is greater than 1:1.
Subsequent steps comprise reacting the two compounds at a first
temperature until substantially all of the R(ao).sub.n--Y has
reacted; thereafter, reacting at a second temperature higher than
the first temperature until substantially all of the excess
isocyanate groups have reacted.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE
INVENTION
[0010] The present invention teaches a parting agent, which
comprises the reaction production of an isocyanate compound and an
isocyanate-reactive compound.
[0011] The isocyanate compounds useful in the present invention
comprise the organic di- and polyisocyanates, modified isocyanates,
isocyanate-terminated prepolymers, and mixtures of these
isocyanates, all described below.
[0012] The isocyanate compound which may be used includes
aliphatic, alicyclic and aromatic polyisocyanates characterized by
containing two or more isocyanate groups. Such polyisocyanates
include the diisocyanates and higher functionality isocyanates,
particularly the aromatic polyisocyanates. Mixtures of
polyisocyanates may also be used and include, crude mixtures of di-
and higher functionality polyisocyanates produced by phosgenation
of aniline-formaldehyde condensates or as prepared by the thermal
decomposition of the corresponding carbamates dissolved in a
suitable solvent, as described in U.S. Pat. No. 3,962,302 and U.S.
Pat. No. 3,919,279, the disclosures of which are incorporated
herein by reference, both known as crude diphenylmethane
diisocyanate (MDI) or polymeric MDI.
[0013] The organic polyisocyanate may be an isocyanate-terminated
prepolymer prepared by reacting, an excess of a polyisocyanate with
a polyol which, on a polyisocyanate to polyol basis, may range from
about 20:1 to 2:1. The polyols include, for example, polyethylene
glycol, polypropylene glycol, diethylene glycol monobutyl ether,
ethylene glycol monoethyl ether, triethylene glycol, etc., as well
as glycols or polyglycols partially esterified with carboxylic
acids including all polyester polyols, and all polyether
polyalkylene polyols. Such polyols are well known in the art and
will not be further described.
[0014] The isocyanate compound may also be modified isocyanates,
such as, carbodiimides, allophanates, isocyanurates, and
biurets.
[0015] Also illustrative of the di- or polyisocyanates which may be
employed are, for example: toluene-2,4- and 2,6-diisocyanates or
mixtures thereof; diphenylmethane-4,4'-diisocyanate and
diphenylmethane-2,4'-diiso- cyanate or mixtures of same, the
mixtures preferably containing about 10 parts by weight 2,4'-MDI or
higher, making them liquid at room temperature; polymethylene
polyphenyl isocyanates; naphthalene-1,5-diisocyanate; 3,3'-dimethyl
diphenylmethane-4,4'-diisocya- nate; triphenyl-methane
triisocyanate; hexamethylene diisocyanate;
3,3'-ditolylene-4,4-diisocyanate; butylene 1,4-diisocyanate;
octylene-1,8-diisocyanate; 4-chloro-1,3-phenylene diisocyanate;
1,4-, 1,3-, and 1,2-cyclohexylene diisocyanates and; in general,
the polyisocyanates disclosed in U.S. Pat. No. 3,577,358, the
disclosure of which is incorporated herein by reference. Preferred
polyisocyanates include 2,4'-MDI, 4,4'-MDI, 2,2'-MDI, polymeric
MDI, and mixtures thereof.
[0016] Typical of the suitable polyisocyanates are those sold under
the trademark Lupranate.RTM. by BASF Corporation. For example,
Lupranate.RTM. MI, an isomeric blend of 2,4' and 4,4' MDI isomers,
or Lupranate.RTM. M20 SB, a polymeric MDI.
[0017] The isocyanate-reactive compound can be represented by the
general structure R(ao).sub.nY. Here Y represents a monofunctional
group which is reactive with isocyanates. Examples include
monoalkylamino and hydroxyl, with hydroxyl being preferred. In the
structure above, (ao) represents an alkylene oxide or mixture of
alkylene oxides selected from the group consisting of ethylene
oxide, propylene oxide, butylene oxide, and mixtures thereof; n
refers to the number of alkylene oxide units in the
isocyanate-reactive compound. It is conventional to use the symbol
(ao).sub.n to represent a polyoxyalkylene chain comprising, on
average, n repeating units of alkylene oxide. In the invention, a
preferred alkylene oxide is ethylene oxide. The variable n can be
integer or non-integer and is in general from about 1 to about 25,
more preferably from about 2 to about 25, and most preferably from
about 3 to about 10.
[0018] In the isocyanate reactive compound R--(ao).sub.n--Y, R
represents a hydrophobic group. The hydrophobic group is based
either on hydrocarbons or on silicon-containing compounds.
[0019] Preferred hydrocarbon hydrophobic groups include in general
those containing alkyl, alkaryl or polyaryl moieties. Alkyl
moieties useful in the invention include those with about 6 or more
carbon atoms. Examples are hexyl, octyl, nonyl, decyl, dodecyl, and
hexadecyl. Useful alkaryl moieties include the aryl hydrocarbons
such as alkaryl, dialkaryl, and trialkaryl hydrocarbons, wherein
the alkyl groups contain at least about 3 carbon atoms. Together
with the 6 carbon atoms of the aromatic ring, there are thus 9 or
more carbon atoms in the preferred alkaryl, dialkaryl, and
trialkaryl hydrocarbons. Examples include octylphenyl, hexylphenyl,
nonylphenyl, dioctylphenyl, dinonylphenyl, trioctylphenyl,
trinonylphenyl, and trialkarylphenyl groups. Particularly preferred
are the alkaryl and dialkaryl groups such as nonylphenyl and
dinonylphenyl. The polyaryl compounds have the general structure of
a polyphenyl structure that is either alkyl substituted or
unsubstituted. Thus in the present specification and claims the
term polyaryl means a polyphenyl structure that is either alkyl
substituted or unsubstituted.
[0020] Examples of isocyanate-reactive compounds useful in the
invention thus include alcohol alkoxylates, alkylphenol
alkoxylates, and dialkylphenol alkoxylates. Examples of alcohol
alkoxylates include the fatty alcohol ethoxylates which are made by
adding 2-20 units of ethylene oxide onto a C.sub.6-C.sub.18
straight chain or branched alcohol. These are available
commercially, for example, under the Iconol.RTM. trademark from
BASF Corporation. Examples of useful alkylphenol alkoxylates
include those made from alkylphenols having three or more carbons
in the alkyl chain attached to the phenol ring. Commonly available
commercial alkylphenol alkoxylates include octylphenol ethoxylates
and nonylphenol ethoxylates which are made by adding about 2 to
about 20 units of ethylene oxide to octylphenol or nonylphenol.
They are sold, for example, under the tradenames Iconol.RTM. OP and
Iconol.RTM. NP by BASF Corporation. Similarly, dialkylphenol
ethoxylates are useful in the invention. Examples are alkoxylates
of those dialkylphenols or trialkylphenols having three or more
carbon atoms in each alkyl group. Especially preferred are the
ethoxylates of dialkyl- or trialkylphenols made by adding about 2
to about 20 units of ethylene oxide to, for example, a
dialkylphenol such as dioctylphenol or dinonylphenol. Dinonylphenol
ethoxylates are available commercially from BASF Corporation under
the Macol.RTM. DNP tradename.
[0021] Where R represents silicon-containing compounds, the
preferred hydrophobic group comprises siloxane groups. Generally
preferred are the dimethylsiloxanes including trisiloxanes and
higher polysiloxanes. A preferred isocyanate-reactive compound
comprises a silicone compound of general structure 1
[0022] wherein Q is a bridging group of one or more atoms, m is
0-10, p is 0-10, R1 and R2 are independently alkyl or alkaryl
groups containing 1 to 18 carbon atoms, (ao) is an alkylene oxide
or mixture of alkylene oxides such as ethylene oxide, propylene
oxide, butylene oxide, and mixtures thereof, Y represents a
monofunctional isocyanate reactive group, and n is from about 2 to
about 20.
[0023] Preferably R1 and R2 are alkyl groups containing 1-10 carbon
atoms. More preferably, R1 and R2 contain 1-4 carbon atoms. Most
preferably, R1 and R2 are methyl. R1 and R2 may be different, but
it is preferred that they be the same. It is particularly preferred
that R1 and R2 are both methyl. The value of m and p are preferably
from 0 to 2; in a particularly preferred embodiment, m and p are
both 0. When m and p are both 0, the compound is a trisiloxane.
Where the sum of m and p is greater than 0, the compound is a
higher polysiloxane. A particularly preferred trisiloxane
containing isocyanate-reactive compound is commercially available
from BASF Corporation as Masil.RTM. SF-19.
[0024] Such silicon containing isocyanate-reactive compounds can be
synthesized, for example, by the reaction of R1,R2-terminated
hydro-functional polysiloxane of general structure 2
[0025] where R1, R2, m, and p have the same meaning as above, with
an adduct of an unsaturated alcohol and alkylene oxides. The adduct
can be prepared by reacting the unsaturated alcohol with ethylene
oxide or a mixture of alkylene oxides in the presence of base
catalysts. Thus, when the unsaturated alcohol is allyl alcohol, the
adduct will have the general structure
CH.sub.2.dbd.CH--CH.sub.2--(ao).sub.n--OH, where ao represents the
ethylene oxide units or mixture of alkylene oxide units, and n
represents the degree of alkoxylation. When the olefin of the allyl
alcohol adduct reacts with the Si--H bond of the hydro-functional
polysiloxane, a bridging group Q is formed consisting of the three
carbon atoms of the ally alcohol portion of the adduct.
[0026] When Y of the isocyanate reactive compound comprises a
hydroxyl group the reaction product will contain urethane linkages
formed from the reaction of the isocyanate groups of the isocyanate
compound with the hydroxyl group of the isocyanate-reactive
compound. Similarly when Y comprises an alkylamino or other
nitrogen containing isocyanate-reactive group, the resulting
reaction product will contain urea linkages, based on the reaction
of the isocyanate groups with the nitrogen of the
isocyanate-reactive compound.
[0027] The parting agents of the present invention may also contain
chemical modifications of the urethane or urea linkage, such as
allophanates, carbodiimides, biurets, and uretonimines. In general
allophanate linkages are formed by the reaction of an isocyanate
group with a urethane group. Generally the allophanate reaction is
carried out with special allophanate catalysts and at a temperature
that is higher than that at which the urethane is formed by the
reaction of an isocyanate with a hydroxyl group.
[0028] The parting agent of the present invention can be prepared
or synthesized by a number of routes. In general, an isocyanate
compound and an isocyanate-reactive compound of general structure
R(ao).sub.nY are charged together into a reaction vessel.
Thereafter, they are allowed to react for a time sufficient to
react out substantially all of the Y groups on the
isocyanate-reactive compound and all of the isocyanate groups on
the isocyanate compound. Preferably there is less than 2.5%
residual free NCO after the formation of the parting agent, more
preferably less than 1.0% and most preferably less than or equal to
0.2% free NCO after the reaction is complete. It is desirable to
have these very low levels of free NCO when using the parting agent
in a binder resin for wood particles, as described below. These low
levels of free NCO prevent migration of the parting agent into the
wood particles. Excess isocyanate reactive compound can be
tolerated because it does not present any such problem.
[0029] Where the isocyanate compound and isocyanate-reactive
compound are charged in stoichiometrically equivalent amounts,
there is produced a parting agent which contains either urethane
linkages or urea linkages, depending on whether Y in the
isocyanate-reactive compound is a hydroxyl group or an alkylamino
group, respectively. For this reaction the reaction temperature is
set at a temperature of about 40.degree. C. to about 100.degree. C.
Higher or lower temperatures can also be used, but the given range
provides good results. The reaction can be monitored by following
the isocyanate number of the reaction product over time. The
reaction can be stopped when the desired isocyanate number is
reached. The reaction will proceed without catalysts. However
urethane catalysts may be added to the reaction mixture. Examples
of suitable catalysts include potassium octoate, zinc
acetylacetonate, potassium hydroxide, and organo tin compounds.
[0030] To form parting agents which contain allophanate linkages,
further steps are required. For example, after charging the
isocyanate compound and the isocyanate-reactive compound in
stoichiometrically equivalent amounts and reacting at a temperature
of from about 40.degree. C. to about 100.degree. C. until the
desired intermediate isocyanate number is reached, a second charge
of the isocyanate compound can be added to the reaction vessel.
Further reaction is then carried out at a second temperature higher
than about 40.degree. C. to about 100.degree. C. for a period of
time sufficient to react the isocyanate added in the second charge.
Along with the second charge of isocyanate compound, it is
generally necessary to also add a catalyst which aids in the
formation of the allophanate groups. Such allophanate catalysts are
known in the art and include zinc acetylacetonate, titanium
tetrabutoxide, and ferric chloride. The allophanate reaction is
preferably carried out at a temperature of about 100.degree. C. to
about 150.degree. C.
[0031] An alternative method for producing parting agents
containing allophanate groups is as follows. First an isocyanate
compound and an isocyanate-reactive compound are charged to a
reaction vessel in an amount such that the molar ratio of the
isocyanate compound to R(ao).sub.nY is greater then 1:1, that is,
such that there is a molar equivalent excess of the isocyanate
compound in the reaction vessel. The mixture thus charged is then
reacted at a first temperature of from about 40.degree. C. to about
100.degree. C. until substantially all of the R(ao).sub.nY has
reacted. The reaction can be monitored by following the free
isocyanate number during the reaction. When the desired
intermediate % free NCO is reached, the mixture is then reacted at
a second temperature higher than the first temperature. The
reaction proceeds until substantially all of the isocyanate
compound has reacted and the free NCO content of the reaction
product is equal to or less than the desired level.
[0032] Although if the reaction is carried out at high temperatures
for a sufficiently long time, an allophanate catalyst is not
absolutely required, it is in general preferred in the last step to
also add conventional allophanate forming catalysts such as those
described above. The allophanate catalysts may be charged to the
vessel prior to the reaction at the first temperature of from about
40.degree. C. to about 100.degree. C. Alternatively, the
allophanate catalysts may be charged after reacting at the first
temperature but prior to the reaction at the second higher
temperature. In general, the allophanate catalyst and the
temperature of reaction are chosen such that during the reaction of
the isocyanate compound and the isocyanate-reactive compound in the
first step, the temperature is lower than that required for
efficient allophanate formation. In the reaction at the second
temperature the temperature is high enough to efficiently convert
the remaining isocyanate groups to allophanate.
[0033] Allophanates can be formed when an amount of isocyanate
compound in stoichiometric excess to that of the
isocyanate-reactive compound is charged to the reaction vessel. As
discussed above, the charge of excess isocyanate compound can be
accomplished in the first step along with the charge of
isocyanate-reactive compound, where the conditions of catalysis and
temperature are such that the excess isocyanate will not react
further with the urethane or urea linkage being formed by the
reaction of the isocyanate compound and the isocyanate-reactive
compound. Alternatively, the excess isocyanate can be introduced
following the reaction of stoichiometric amounts of
isocyanate-reactive compound and isocyanate compound.
[0034] In either case, in general, any amount of excess isocyanate
can be added to the reaction mixture. However, it is preferred in
making the parting agent of the present invention to use an excess
of isocyanate compound on the order of about 1 to 10 equivalent
percent. That is, there should preferably be about a 1 to 10
percent excess of isocyanate groups over isocyanate-reactive
groups. It can thus be seen that when parting agents of the present
invention are made which contain allophanate linkages, the
compositions will also in general contain urea or urethane
linkages.
[0035] The parting agent and the organic di- or polyisocyanate
which comprises the binder resin should be chosen such that they
are compatible. That is, the two components should be readily
soluble in each other, so that a single phase composition can be
obtained. To this end, it is preferred that the organic di- or
polyisocyanate and the isocyanate compound on which the parting
agent is based should have a similar structure. Therefore, a
preferred binder resin is one where the organic di- or
polyisocyanate comprises an aromatic di- or polyisocyanate and
wherein the isocyanate compound on which the parting agent is based
is also aromatic.
[0036] Preferred organic di- or polyisocyanate include
methylenediphenyl diisocyanate isomers such as 2,4'-MDI, 4,4'-MDI,
2,2'-MDI. A suitable isocyanate compound is Lupranate.RTM. MI,
which is a mixture of 2,4' and 4,4'-MDI isomers, available from
BASF Corporation. Another preferred organic di- or polyisocyanate
is polymeric MDI. Mixtures of the above preferred di- or
polyisocyanates may also be used. A particularly preferred
polyisocyanate comprises polymeric MDI. A useful commercially
available polymeric MDI material is Lupranate.RTM. M20S isocyanate
sold by BASF Corporation.
EXAMPLES
[0037] Example 1 below describes the synthesis of a parting agent
wherein the isocyanate compound is a mixture of diphenylmethane
diisocyanate isomers, R comprises dialkaryl, Y is hydroxyl, and n
is about 10. Example 2 describes the synthesis of a parting agent
wherein the isocyanate compound is a mixture of diphenylmethane
diisocyanate isomers, R comprises trisiloxane, and Y is hydroxyl.
Example 3 demonstrates formation of a parting agent wherein the
hydrophobic group is an alkaryl. Example 4 is similar to Example 3
with the addition of a catalyst.
[0038] Lupranate.RTM. MI isocyanate is a mixture of
diphenylmethylene diisocyanates sold by BASF Corporation.
Macol.RTM. DNP-10 is an average 10 mole ethoxylate of
dinonylphenol, and Iconol.RTM. NP-6 is an average 6 mole ethoxylate
of nonylphenol; they are commercially available from BASF
Corporation.
[0039] In any of the reactions the order of addition of the
components can be changed without altering the product.
Example 1
Synthesis of an Internal Parting Agent where the Hydrophobic Group
is Dialkaryl
[0040] Macol.RTM. DNP-10 surfactant (428.4 g) is placed in a one
liter two neck flask and heated to 45.degree. C. With continuous
agitation, Lupranate.RTM. MI isocyanate (71.6 g) is added dropwise
over a period of an hour. The temperature is increased to
80.degree. C. and the reaction is continued for 20 to 24 hours.
Titration of remaining free NCO groups shows a % free NCO of about
0.5%. The temperature is maintained for an additional one hour, the
reaction mixture is cooled to room temperature and allowed to stand
overnight. Titration of free NCO after the overnight period shows
the reaction is complete--that is, the measured free NCO is 0.1%,
which is within the error of the method of detection.
Example 2
Synthesis of an Internal Parting Agent where the Hydrophobic Group
is Silicon
[0041] Masil.RTM. SF-19 surfactant (423 g) is placed in a one liter
three neck flask and heated to 80.degree. C. with continuous
agitation provided by an overhead stirrer. Lupranate.RTM. MI
isocyanate (77 g) is added dropwise over a period of about 30
minutes. The temperature is increased to 90.degree. C. and the
reaction is continued for 20-24 hours, after which time the % free
NCO is determined by titration and found to be about 0.5%. The
reaction is continued for an additional 2 hours at 90.degree. C.,
the reaction mixture is cooled to room temperature and allowed to
stand overnight. Titration of free NCO shows the reaction is
complete.
Example 3
Synthesis of an Internal Parting Agent where the Hydrophobic Group
is Alkaryl.
[0042] Iconol.RTM. NP-6 (393.5 g) is placed in a one liter two neck
flask and heated to 45.degree. C. With continuous agitation,
Lupranate.RTM. MI (106.5 g) is added dropwise over a period of one
hour. The temperature is increased to 80.degree. C. and the
reaction is continued for 20 to 24 hours. Titration of remaining
free NCO groups shows a % free NCO of about 0.5%. The temperature
is maintained for an additional one hour, the reaction mixture is
cooled to room temperature and allowed to stand overnight.
Titration of NCO the following morning shows the free NCO is 0.1%,
which is within the error of the method, thus the reaction is
complete.
Example 4
Synthesis of an Internal Parting Agent where the Hydrophobic Group
is Alkaryl.
[0043] Lupranate.RTM. MI (106.5 g) is placed in a one liter two
neck flask and heated to 45.degree. C. With continuous agitation,
Iconol.RTM. NP-6 (393.5 g) and 20 ppm of the urethane catalyst
DABCO T-12 is added dropwise over a period of an hour. The
temperature is increased to 80.degree. C. and the reaction is
continued for 9 hours. Titration of remaining free NCO groups shows
a % free NCO of about 0.5%. The temperature is maintained for an
additional one hour, the reaction mixture is cooled to room
temperature and allowed to stand overnight. Titration of NCO the
following morning shows the free NCO is 0.1%, which is within the
error of the method, thus the reaction is complete.
[0044] Procedure For Evaluation Of Internal Press Release Agent
[0045] The following procedure was used to test the parting agents
of the present invention prepared as in Examples 1-3. Results of
the experiments are given in Table 1 below.
[0046] 1. The stainless steel caul plates are preconditioned with
external mold release (i.e. spray a dilute solution of external
press release on the caul plate, then wipe off the excess with a
paper towel). In the Examples, XCTW-9495, a water based
organosiloxane was used as the external mold release.
[0047] 2. Raw material (wood fiber, wood flake, wood particle, saw
dust, etc.) is blended with a binder resin comprising
Lupranate.RTM. M20SB, which is a polymeric MDI sold by BASF
Corporation, a parting agent prepared according to the present
invention, and, optionally, a synergist component to form a furnish
material. The optional synergists include the lower N-alkyl
pyrrolidones. In general, the C.sub.1-C.sub.4 N-alkylpyrrolidones
are useful in the present invention, with the preferred N-alkyl
pyrrolidone being N-methyl-2-pyrrolidone (NMP). Other useful
synergists include gamma-butyrolactone. Mixtures of the above
synergists can also be used to form the synergist component. The
synergist component can be combined with the polyisocyanate
component in an amount of from 0.5 to 25 weight percent based on
the total weight of the binder resin. More preferably, the binder
resin includes from about 0.5 to 15 weight percent, and most
preferably from about 0.5 to 10 weight percent synergist based on
the total weight of the binder resin.
[0048] 3. The parting agent and synergist used, are reported in the
Examples as weight percent based on the total weight of the binder
resin. Between 2.5% and 10% by weight binder resin is used, based
on the total weight of the raw material lignocellulosic particles.
The amount used is reported in the Examples. In the Examples, the
lignocellulosic particles are either sawdust or medium density
fibers (MDF).
[0049] 4. A form is used to set the desired size of the board, the
furnish material is layered on the bottom caul plate. In the
Examples, a 6 inch by 11 inch aluminum form is used. The caul plate
is transferred into the press and covered with another
preconditioned caul plate.
[0050] 5. The material is pressed under heat and pressure to
produce a board using typical conditions. Pressing time and
temperature vary with board thickness and the raw material. In the
Examples, the boards are pressed for 2 minutes at 350.degree. F.
and 520 psi. The press is opened and the caul plates and board are
removed from the press.
[0051] 6. A successful event is one after which the board (a) is
readily removed from the caul plates without difficulty, (b)
without leaving residue on the caul plates and (c) without causing
surface imperfections on the board resulting from sticking.
[0052] 7. Repeat steps 2-5 using the same set of caul plates
without applying any additional external press release.
[0053] 8. The number of boards successfully made is a measure of
the performance of the parting agent. The higher the number, the
better the parting agent. The percent binder resin used is a weight
percent based on the total weight of the raw material.
1TABLE 1 Wt. % Wt. % Parting parting synergist agent agent in Wt. %
in # of Raw in binder binder binder the binder boards Example
material resin resin used resin pressed 1 MDF Example 3 10 4 none 5
2 MDF Example 2 10 4 none 9 3 MDF Example 2 10 4 10% NMP 6 4 MDF
Example 2 5 4 5% NMP 6 5 Sawdust Example 1 5 4 none 7 6 MDF Example
1 5 4 5% NMP 12 7 MDF None 0 4 none 1
[0054] Example 7 is a control where no parting agent was used in
the binder resin. With no parting agent, only one board could be
pressed before re-applying the external release agent. Examples 1-6
show that the parting agents of the present invention impart
desirable properties to the binder resins of the present invention,
in that their use in the binder resins enables 5 to 12 boards to be
pressed without re-application of the external release agent.
[0055] In addition, all binder resins in Examples 1-6 are of a
single phase and homogenous, indicating that the parting agent is
compatible with the di- or polyisocyanate, and that the binder
resins are stable.
* * * * *