Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
38~
ADHESIVE COMPOUND PARTICULARLY FOR MANUFACTURING WOOD
CONSTRUCTIONS, PANELS AND OTHER SIMILAR WOOD PRODUCTS
The present invention relates to an adhesive compound
for manufacturing wood constructions, panels and
other similar wood products, one component of the
adhesive compound being resorcinol-phenol resin.
Resorsinol-phenol adhesives are as such known in the
prior art. The main ingredients of these adhesives
are resorcinol, formaldehyde and phenol. The ad-
hesive is manufactured in a reactor where the inure-
dints are put under a suitable pressure and temper-
azure. The reaction is interrupted at the procaine-
densatlng stage. If the adhesive is used, for
instance, in the manufacturing of glued laminated
beams and other wood constructions, the reaction is
completed by adding a hardener, for instance formal-
Dodd, to the compound.
Among the drawbacks in the use and production of
resorcinol~phenol adhesives are their high price and
the fact that the raw materials are difficult to
obtain.
The purpose for employing the adhesive compound of
the invention is to eliminate some of the Defoe-
gullies connected to the availability of the raw
materials, particularly resorcinol, and to help
produce a new, more economical resorcinol-phenol
based adhesive compound.
In accordance with the present invention, there is
provided a resorcinol~phenol resin based aqueous
adhesive composition, comprising a harden Abe mixture
of guy by weight resorcinol-phenol resin/ the dry
matter content of which is 30-60% by weight, and
60-10% by weight humus substance extract prepared
from peat, the percentages being based on the total
composition. The extract is prepared by treating dry
ground peat with an aqueous alkaline solution having
an alkaline concentration of up to about So and
sufficiently to extract into the solution the extract
table humus content therefrom without extracting the
lignin contained in the peat and such that the lignin
remains in the solid matter of the peat and drying
the alkaline solution extracted humus substance
content, and grinding the dried humus substance
content and then admixing it with water to form the
extract. The composition further includes 5-20% by
weight formaldehyde or paraformaldehyde based on -the
mixture as hardener.
The adhesive compound of the present invention brings
forth the following advantages compared to the
currently used resorcinol-phenol adhesives. Part of
the resorcinol-phenol resin used in the adhesive
compound can be replaced by a
I
to
humus substance extract made of peat, preferably decomposed
peat, or by a commixture made of humus substance extract
and formaldehyde. Experiments have shown that roughly half
of the adhesive compound can be replaced by the humus
substance extract. The extract is easy to produce, and so
is the adhesive compound according to the invention. In
countries where there are bogs or mire terrains, peat is
always available. The humus substance extract can also
replace various fillers, for instance wood dust, currently
lo used in resorcinol-phenol adhesives. This extract is
remarkably cheaper than -resorcinol-phenol resin. The price
ratio at present is about 1:10. Moreover, the adhesive
compound of the present invention provides for a strong,
weather-proof adhesion which fulfill the requirements of
the so-called exterior adhesion class stipulated in the
wood construction standards and norms in several countries.
Humus substance extract has not earlier been utilized as
the raw material of adhesives. The initial material of the
humus substance extract is the decomposed or
semi-decomposed section of peat. The structure of the peat
layer from the ground surface, i.e. from the slightly
decomposed top layer, down to the decomposed bottom layer
is illustrated in the appended Table 1. The decomposition
rate is measured according to the scale H1-H10
(Humidification value).
Decomposed peat contains the greatest proportion, about
50-60 I, of humus substance, the utilization whereof is the
main point of the prevent invention.
Humus substances, particularly humid acids contain
polyphenolic compounds, the origin and structure whereof
still remains partly unknown. According to two popular
theories, they are created either a) when lignin is
decomposed due to the influence of microorganism (the
, ,
I
TALE 1
¦ ¦ SLIGHTLY ¦ CARBOHYDRATES 30-50
5 ¦ ¦ DECOMPOSED ¦ LIGNIN 30~40 Jo
¦ ¦ Ho - Ho ¦ HUMUS SUBSTANCE 0-5
¦ CARBOHYDRATES 15-40 on
PEAT ¦ SEMI-DECOMPOSED ¦ LIGNIN 5_30 v
lo SLAYER ¦ Ho - Ho ¦ PEAT WAXES AND RESINS 5-15~ ¦
l j ¦ HUMUS SWEETNESS owe
¦ ¦ RECOMPOSED ¦ CARBOHYDRATES 0-2
l l ¦ LIGNIN 5-20
lo ¦ I H 9 - H 10 ¦ PEAT WAXES AND RESINS 5-20~ ¦
I I . ¦ HUMUS SUBSTANCE 50-60~ l
lignin theory) or b) in a micro-biological process from the
carbohydrates and proteins of dead plants (the polyphenol
theory). The structure of polyphenolic compound rumble
that of finlike acid and tannin. Part of the basic
structure is formed of garlic acid, i.e. the sums substance
which is one of the main components in ~uebracho extracts
and in bark extracts. In the adhesive compound according to
the invention, formaldehyde reacts with the activated
carbon which takes up the potion no the garlic acid,
and forms a polymer of the phenol rosin type. In addition
to this, the humid acids contain resorcinol; which Allah
forms a strongly-bound polymer with formaldehyde even at a
low temperature.
The major part of humus substances, i.e. the humid acid,
can by separated from peat by means of alkaline water
solution It it pointed out that the empuyed alkaline waler
solution art mild 5 I, in which cave thy lignin
contained in the peat is not separated into the extract but
remains in the solid matter.
The present invention is illustrated in more detail in the
following examples describing the production methods of the
humus substance extract and the adhesive compound.
Production of humus substance extract from put means of
alkaline solution
When peat is extracted in a mild 1-5 Nash water solution,
the weight proportions of the various ingredients are for
example the following:
For example: 1 port by wright dry peat ground)
1û parts by weight distilled water
10 6 by weight Noah (of the dry peat amount)
The ingredients are put in a vessel where the temperature
is raised up to 8ûC, and the compound is continuously
mixed. The treatment is carried on for 1 hour. Thereafter
solid matter are separated from the extract solution by
means of a centrifugal air-separator. The solids are
removed and the extract solution is recovered and dried for
instance in an incubator in the temperature of 50C. The
extract recovery of the peat extract extracted in this
fashion is about 6û of the dry peat amount.
1. Production of humus substance extract adhesion coy Lund
The humus substance extract it ground fine in a hammer mill
or in a disc refiner, where the blade position is 0,2 my
The weight proportion of the ingradisnts in the compound
us
1 part by weight humus substance extract
2 part by White water.
,
8g
A desired amount of the compound obtained in this fashion
is added to a given resorcinol-phenol resin amount.
2. Production of humus substance extract adhesion compound
The humus substance extract is ground fine in a hammer mill
or in a disc refiner after the same fashion as above.
Paraformaldehyde is added to the extract. The weight
proportions of the ingredients in the compound are:
1 part by weight humus substance extract
10-20 OX by weight paraformaldehyde of the
extract weight
2 parts by weight water
A desired amount of the compound obtained in this fashion
is added to a given resorcinol-phenol resin amount.
The preferable ingredient proportions in the adhesion
compound of the invention, i.e. in the humus substance
adhesion compound, are the following:
- resorcinol-phenol resin 4û-90 by weight. The dry matter
content thereof is 30-40 JO by weight.
- humus substance extract made of poet 10-60 by weight,
which extract is prepared for example according to the
productiorl methods described above.
An amount of water, 0-20 OX by weight, can be added to the
compound in order to provide for the necessary vacua fly.
before using the adhesion compound an amount of some
hardener, 5-2û I, is added thereto. For instance
formaldehyde can be used a the hardener.
EXAMPLE 1
An adhesion compound according to Table 2 was made of humus
substance extract and resorcinol-phenol resin. The
composition of a respective ordinary resorcinol-phencl (RF)
adhesive is also presented in Table 2.
TABLE 2
i
lûrdinary RF_adhesion comeoundl Extract adhesion compound
Resorcinol-phenol resin: ¦ Resorcino-phenol resin: ¦
¦ 10û parts by weight ¦ 50 parts by weight
¦ Hardener (+ filler): ¦ Humus matter extract:
I 15 parts by weight I 50 parts by weight
I I Hardener:
¦ 15 parts by weight
I
The adhesion compound according to the invention was
employed for sizing a 6-lamellated glued laminated beam. The
adhesive was spread by means a a spatula, and the adhesive
amount we about 303 g/m2; clamping pressure 8 kp/cm2,
pressure time 4 h, temperature 25~C. The measures of the
redeemed test beam wets: length 600 cm, height 1~0 cm (6
lamely) and width 1~0 mm; material Spruce. Thy beam was
left to rest for 4 days in the 65 Z Al condition.
Thereafter test pieces were sawn off for the following
tests:
1) Delamination Tao a wording to the American Standard
ASTM D 11û1-59. In this text the test piece ate moisture
and dried two times. The duration of thy test it about 8
days.
I) The glue joint block-shsar teat according to the
American Standard ASTM ~05-4~.
,
The test results were the following:
1) The delamination test result was 5 0;
2) The glue joint block-shear test results were, as the
average of 20 pieces 9,29 N/mm2, and wood failure 95 I.
According to the Standard ASTM D 1101-59, the delamination
percentage must not surpass 5 0 after the two-phase test.
In the block-shear test of the Standard ASTM D 90S-49, the
glue joint shearing strength according to Nordic
regulations must be at least 6 N/mm2, and the wood failure
must be at least 50 JO. The obtained results thus fulfill the
stipulated requirements.
EXAMPLE 2
The commixture of peat extract and resorcinol-phenol
adhesive was tested for adhesion in room temperature. The
adhesive compounds are presented in Table 3.
TABLE 3
¦ Material Compound
¦ ¦ (weight proportions) ¦
I I Us 1 Us 1 Us I Y I
1 _ I I 1 1- - I
¦ Resorcinol-phenol resin (RF-30) ¦ 45 ¦ 40 ¦ 43,5¦ 87 ¦
¦ Hardener ¦ 5 ¦ lo ¦
¦ Humus substance extract powder ¦ 14 ¦ 20 I 17 ¦ - ¦
¦ ParaFormaldehyde ¦ 2 ¦ 4 ¦ 4 ¦ - ¦
¦ Water ¦ 34 ¦ 36 ¦ 34~5¦ ¦
_. . . 1 1- 1 1 . I
The adhesive compound Us was employed for sizing a hem
made of 33 x 120 mm spruce boards, the length of which was
550 mm and height 165 mm (5 lamely).
fix
The adhesive speed amount was 400 g/m2, pressure time 3,5
h, clamping pressure kp/cm2 and pressure temperature +
25C.
The glue joint shearing strength of the beam was measured
according to the American ASTM D 905 Standard (the
block-shear test); the average shearing strength obtained
for 20 test pieces was 9,5 N/mm2, standard deviation 1,6
N/mm2, and the characteristic shearing strength value 6,3
N/mm2. The respective strength of the glue joint in
glued laminated beam structures must be 6,0 N/mm2O
The adhesive compounds Us, Us and the normal RF-30 (V)
adhesive were used for sizing the close-contact test pieces
according to the So 1204, which test pieces are used in
the Nordic acceptance test for beam adhesives. The row
material employed was birch. The pressure time in room
temperature was 5 hours. The test pieces were tested 2 days
after the sizing. The received readings for the glue joint
shearing strength were (average values for 10 pieces):
Adhesive compound Us: 4,46 N/mm2 dry
3,93 N/mm2 after 6 h boiling
Adhesive compound Us: 4,79 N/mm2 dry
Adhesive compound V: 4,78 N/mm2 dry
Compared to the refrains adhesive V (RF-30), the sizing
quality with the humus extract adhesive compound, when
tested dry, is as good when half of the RF rosin is
replayed by a mixture of humus extract and water Us The
OHS. 1204 demand for the shearing strength of a glue joint
after 6 hours' boiling is 2,4 N/mm2, which is also easily
surpassed when the humus extract - water mixture amount it
even more thin half of the amount a thy RF rosin .
